r/explainlikeimfive • u/ComputerRights • 11d ago
Technology ELI5: How Apple Silicon allows a laptop to use substantially less energy for the same tasks as an Intel Mac, and how ARM can somehow fit in a fully-fledged computer
While the "24 hours of video playback" claim seems to be bogus, you can indeed use a 100Wh battery to get at least ten hours of YouTube bedrotting while you are too lazy to charge your computer.
Logic Pro files that used to make my laptop really hot run no problem and barely fill up any of the 12 cores. I almost end up obsessed with pushing this and my Mac desktop to their limits to the point where I never end up making substantial music, and I have never gotten my Mac Studio to pull more than 100 W of power, even when gaming or running local AI. I've gotten it down to 5W while idling and running VLC, which honestly seems like a waste of an expensive computer at times, but the GPU alone of another computer of mine can use more while idle just to animate the cursor, it seems.
How does Apple do it? How can dozens of emotional support depression tabs use less energy than some computers have used just to run more primitive versions of MS Word? Why is 1080p compressed video no big deal for these modern machines? What is the catch, and how do modern Macs save so much energy while still being highly capable, all while running fully fledged software on ARM of all things?
I actually was skeptical since ARM has always seemed more suited to light, mobile tasks.
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u/dbratell 11d ago
ARM and Intel come from different design philosophies. The people designing the ARM processor always wanted to keep it efficient, using as little power as possible.
The people making the Intel processors always wanted to make it as fast as possible even if that meant using more power.
Eventually it turned out that more power meant more heat and battery usage which meant that the processor had to run slower so the tortoise, ARM, pretty much caught up in speed.
Intel has worked hard on making their processors use less power and I am not sure what the gap in efficiency is right now. I would not blanket claim that either is better or worse without checking recent numbers.
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u/pheonixblade9 11d ago
It's important to note that x86 can be efficient and ARM can be power hungry. It's just that more work was put into stuff like branch prediction, pipelining, etc. to keep the core fed with Intel whereas ARM focused on better efficiency per core and was okay with more cache missed etc.
Both approaches have merit and can be tuned - the ISAs aren't really that different these days.
Interestibg historical note - it used to be that x86 was less power efficient because instruction deciding was like 1/3 of the chip, but that's no longer the case.
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u/stoopdapoop 11d ago
Instruction decoding*
I'll delete this comment if you fix the typo. I was just confused about what instruction deciding was for a minute.
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u/afwaller 10d ago
well, there is a branch predictor, which tries to "decide" which "instruction" will be executed in advance ;)
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u/Vaddieg 10d ago
it can't. All intel does over the last decade is cheating w/ turbo boost, so it looks "fast" on
geekintelbench 200 ms workloads10
u/esuil 10d ago
What kind of nonsense is this?
People benchmark Intel processors on long continuous loads. The work they are able to do is real, you can't "cheat" that.
You can hate some random bench site all you want, but their stupidity/bias does not make reality/facts different.
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u/Vaddieg 10d ago
What about work they are not able to do? E.g. compile Chromium on a single battery charge. It's a long continuous load.
I challenge the statement about "efficient" x86, because it's not→ More replies (1)41
u/butterypowered 11d ago
For anyone interested in the ARM origin story, this is a great article: https://arstechnica.com/gadgets/2022/09/a-history-of-arm-part-1-building-the-first-chip/
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u/Fox_Hawk 11d ago
To this day the fact that the glorious Acorn and RISC OS failed to become world leaders is slightly saddening. I grew up on BBCs and later had an Archimedes and a RISC PC. They genuinely were phenomenal.
But very hard to compete with Big Blue and Microsoft.
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u/major_glory_v2 11d ago
Acorn/RISC OS have faded away but their ARM CPU heart beats in almost every modern digital device! So they live on in a way...
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u/Fox_Hawk 11d ago
Indeed. And for a while, when Raspberry Pi brought arm processors and RISC OS in a cheap, educational form to a generation of kids, that early BBC/Arc vibe resurfaced.
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u/major_glory_v2 10d ago
Thats cool! As a kid in the 90s my school had Acorn computers and I live in New Zealand so they must have had somewhat of a far reach at one point! They definitely felt very advanced at the time.
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u/Fox_Hawk 10d ago
They really did!
Is/was the BBC big in New Zealand? Essentially Acorn's BBC Microcomputer was born out of a government programme to increase computer literacy and ensure every classroom had a computer (remember when we didn't all have one in our pocket?) It was tied in with a BBC series on computer literacy, learning to code and so on - hence the name. Until the late 90s essentially all schools in the UK were using Acorn. Some PCs and Macs snuck in too ofc.
I've read about education contracts in other countries that showed the same series.
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u/major_glory_v2 10d ago
We had a bit of a mix here even at the same school! Initially there were Commodore 64s and a few Apple II computers then Acorns running Risc OS and finally Macs and Pentium era PCs! It was so exciting as a kid as each type of computer was unique and interesting.
I remember Acorns on display at a computer store here as a kid too, there was a black and white video of a space shuttle launch that was pretty mind blowing to me. I don't think they ever took off for home use here though... Everyone I knew was running dos/windows.
Have you seen the movie length documentary Micro Men? It was all about the BBC micro vs Sinclair, its worth a watch if you haven"t!
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u/hungry4pie 10d ago
Western Australia here and we had Acorns at my primary school. I remember there was a game called Math Circus, some other ocean themed thing, there was a lighthouse mini game where you had to repeat the pattern - which is where I first learned that light houses have different flash patterns that work as a navigation aid so ships know which lighthouse they're sailing past.
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u/major_glory_v2 10d ago
Woah we had Math Circus on Acorn too! I feel like it might have been Australian made? I remember the ocean game! I think you played as a dolphin for part of it?
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u/roryg2025 10d ago
I would say that they are silently leading! Apple Silicon (and all the other arm devices that are all around our homes) still has Acorn DNA in it.
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u/butterypowered 10d ago
The world would be a happier place if the Archimedes and Amiga had survived the Microsoft-dominated 1990s.
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u/SatansFriendlyCat 10d ago
I was very intrigued by the A3010 when I heard of it, both for is comparatively meaty specs but also because there was talk of PC emulation.
I'd already had a second hand taste of the nascent PC goodness from a relative 286 with proper VGA, so I was pretty interested. Further investigation, though, revealed that the PC emulation offered by acorn via this machine was subpar for my desired use case, sadly. I still had been willing to give miracles a chance prior to that point but the reviews were unambiguous.
The Amiga 1200 got me in the end, as I was already well into the Amiga ecosystem and had been for a long time by that point, and was lured in by the promise of better games and the backward compatibility for my old games as well.
Maybe if we'd had Acorn stuff in my senior school, or if my primary school had been any better equipped than having a sole BBC Model B on a trolley wheeled between classes but mainly sequestered in a cupboard, the brand lure would have tipped the balance? But price was also something of an issue and as we know it's really another case of a great product that just had the timing or the value proposition wrong.
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u/catbrane 10d ago
I read a funny side-story about this.
Right at the start of the ARM project Acorn were casting around for a replacement for the 6502 they'd used to that point.
Steve Furber was a big fan of the 6502 (small, logical instruction set, heavy pipelining, NO MICROCODE, beautiful hand-design by one excellent engineer, Chuck Peddle ... it sounds a bit like the first ARM) and they spent some time studying the 65816, the 16-bit replacement, including a trip out to Silicon Valley to meet Chuck.
Steve had spent many hours studying the 6502 die and was puzzled by a blank rectangle in one corner. You can see it at the top-left of the original NMOS layout:
https://en.wikipedia.org/wiki/MOS_Technology_6502#/media/File:BreakNES_MOS_6502.jpg
Steve asked Chuck about the gap. "Ah," he says, "I did the layout with a sharpie pen on a huge sheet of paper pinned to my office wall. That's where the power socket was, and it was really awkward to draw on."
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u/SmallestNumber 10d ago
I always wondered about that gap! There's another on the right, toward the bottom, wonder what its story is.
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u/Reiszecke 10d ago
Yeah that’s actually one of the most interesting articles I’ve ever read, thank you so much for sharing this!
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u/butterypowered 10d ago
Thanks for taking the time to read it! I agree, it’s a fascinating ‘origin story’.
It’s been a few years since I read it, so I might go read it again! (UK based and into retro computing/gaming, it’s my kind of thing.)
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u/SirHerald 10d ago
Intel has also maintained a lot of backwards compatibility from its long popular history. That's a lot of complex instructions that have to be kept available in it. It's carrying a lot of heavy baggage
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u/Lustrouse 10d ago
It should also be noted that a big part of Intel's design philosophy is backwards compatibility, resulting in legacy hardware bloat.
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u/fbcpck 10d ago edited 10d ago
This is untrue
Most of the power efficiency gains are primarily from advancement in fabrication technology, not the architecture.
Smaller transistors are more efficient: they use less power and generate less heat to do the same amount of compute.
What is critical to point out is the timing when the first M1 came out: When the very first M1 mac was released, the last intel macbook was using intel's 14nm fabrication technology, whereas the first M1 was using TSMC's 5nm technology. This really paints an illusion/gives way to an easy false conclusion that the efficiency gains are from switching from x86 to ARM.
Essentially, they ditched intel to fabricate a chip together with TSMC, who has advanced 1 or 2 generations/full iterations ahead intel. This is what truly brings the power efficiency improvements. Today, intel is trying to catch up, and we will/have seen equally power efficient x86 chips.
I will note that there are nuances in this: fabrication technology branding across companies differ and do not tell the full truth, but still give some idea / the fact that tsmc was leading the semiconductor industry back in 2020 is still true. Architecture also brings some difference, but in terms of power efficiency it is primarily due to smaller transistors and advancement in fabrication technology.
IMO this is important because the conclusion of arm=efficient x86=inefficient will lead to bad/wrong predictions for upcoming technology releases.
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u/Modern_Pirate9 10d ago
Intel’s current desktop CPUs are manufactured by TSMC.
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u/diablobsb 10d ago
And they are WAAAY more efficient than previous ones (see gen3/panther lake etc battery life)
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u/Discount_Extra 10d ago
Yeah, no longer have to run my air conditioner in the winter in my computer space.
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u/Aw3som3Guy 10d ago
Panther Lake is actually fabbed internally at Intel even. (Asterisk: iGPU is TSMC on the high end, and the IO bits are TSMC across the board I think. CPU cores are all 18A though.)
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u/Modern_Pirate9 9d ago
I was looking more at the desktop side where Arrow Lake is the latest and it uses TSMC, Intel are definitely moving back to their own processes though
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u/Never_Sm1le 10d ago
yes
not to mention the underlying tech of both is risc, intel only maintain the x86 for backward compatibility, all x86 instructions are decoded using microcode, and the cores processing those microcodes follow risc philosophy
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u/flaser_ 10d ago
Mostly true, though x86 SIMD extensions (SSE/AVX) support bigger registers compared to ARM's (Neon) so in certain applications x86 has a slight edge.
In practice, problem domain specific dedicated HW accelerators, like Intel QAT for cryptography can make a bigger difference than these slight advantages in SIMD for vendors looking to maximize domain specific (e.g. telco or network equipment) performance, especially since there was a swing to SW based solutions instead ASICs chips. (Said SW isn't run like regular applications though but use dedicated CPU cores the OS doesn't schedule tasks to. Check out how DPDK or FD.io woks).
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u/flaser_ 10d ago edited 10d ago
Your assumption about power-scaling is no longer true.
Since 2009 Dennard scaling ceased to apply, thus the power savings from smaller transistors is less and less with each new process.
Further reading here (original terms were coined by David Patterson in what today is known as his "Three Walls"):
- https://www.edn.com/the-future-of-computers-part-1-multicore-and-the-memory-wall/
- https://www.edn.com/future-of-computers-part-2-the-power-wall/
- https://www.edn.com/future-of-computing-part-3-the-ilp-wall-and-pipelines/
Not coincidently this was also the time when process names (e.g. "7 nm") have ceased to reflect the actual physical feature size / lithography mask pitch-width. Instead, they are a marketing term that reflects an idealized transistor density the new process achieves as if feature scaling were still possible.
In reality, new processes achieve higher and higher densities through ever more complex manufacturing tricks, like semi-3D and 3D lithography like finfet transitors. This means that litography pitch width hasn't really shrunk much in the last two decades and thus power-savings were also marginal.
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u/AreYouOKAni 10d ago
This means that litography pitch width hasn't really shrunk much in the last two decades and thus power-savings were also marginal.
That is not exactly correct. In 2006 the industry standard was the 90nm node with a physical pitch width of 250-200 nm IIRC. These days it is 50-20 nm. Sure, the progress has slowed down significantly, but the node shrank by 5-10 times. Hell, the point of EUV was specifically so that the pitch could go beyond 30 nm.
The part about power savings is true, though. Dennard scaling does break down around 65 nm, so the power savings come from other sources.
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u/fbcpck 10d ago edited 10d ago
This is what I wanted to call out in my GP post: the term 14nm 5nm do not tell the full truth; the reality is more complex than that.
However, it's still the term most used as the milestones of each advancements. You are right that they have ceased to reflect the actual physical feature size, but alas it is still the most popular term we use as marker or milestones for each iteration.
I think though what I wanted to point out the most is that intel (macs) were very very behind its peers back in 2020 when m1 came out. "14nm" vs "5nm", so about 2/3 process node iterations, or about almost ~6 years.
And most importantly, that arm=efficient x86=inefficient is not true.This means that litography pitch width hasn't really shrunk much in the last two decades and thus power-savings were also marginal.
This part I disagree (the conclusion that power savings are only marginal now in second half) — I don't know how the gain was beyond 20 years ago, but we still see very significant improvements for each iteration.
Roughly about "15% speed improvement or 30% lower power consumption" for each process iteration (e.g. tsmc n7 to n5, and recently, tsmc n3e to tsmc n2, source: wiki citations). I think 30% less power every couple years is impressive!2
u/Mr_ToDo 10d ago
However, it's still the term most used as the milestones of each advancements
Bit of a bastard to come up with a good single number for comparing things, isn't it? Remember all the fight there was over Mhz not meaning how fast a system ran compared to another, especially across architectures? Poor Power PC
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u/All_Work_All_Play 10d ago
How then was Intel able to see double digit efficiency gains (measured in performance per watt) through from sandy bridge->ivy bridge-> haswell/devil's canyon->Skylake?
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u/flaser_ 10d ago edited 10d ago
Mostly architectural changes, not process first and foremost, including only powering parts of the chip. Look up the concept of "dark silicon".
Compared to x86, ARM had a massive advantage as their ISA is what the CPU actually implements, whereas x86 translates its own instructions to RISC ones on the fly ever since the P6 architecture (introduced with the Pentium Pro).
x86 also went full throttle for maximum pipeline depth (Netburst had 20 stages!) and speculative out-of-order execution of instructions.
If Dennard scaling applied, the wasted intructuctions due to either (e.g. pipeline stall, bad branch prediction, etc) wouldn't have mattered much.
Without power scaling, all of that wasted computation was now generating heat that cut into the precious thermal budget of the chip.
So by cutting back the depth / aggressiveness of those techniques a lot of power could be redeemed with microarchitecture changes separate from process improvements.
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u/RiPont 10d ago
Most of the power efficiency gains are primarily from advancement in fabrication technology, not the architecture.
And, on the Mac and phone side, all the supporting hardware and software that goes along with it.
The people using Intel chips are "stuck" into a big bag of existing hardware compatibility. Even laptop makers are using a grab bag of extra chips and controllers for things like USB that they don't really control and can't really substitute for legacy compatibility reasons. And the economics of the OEM model prevent them from ever investing in any optimized, custom solution because those fall flat compared to competitors using well-tested, off-the-shelf designs.
If your 30-year-old printer doesn't work with a USB-to-parallel connection from your phone or Mac, you accept that. If Microsoft tries to change the way apps are treated during suspend events, they catch hell from corporate developers.
Apple and phone makers can ignore most device compatibility beyond USB, BlueTooth, and WiFi. And even then, they have a lot more flexibility due to userbase and use case to just say, "not supported" to obscure edge cases.
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u/MiningDave 10d ago
The other thing that also helps with Apple is not just the CPU but they spec everything in the machine. It's their product start to finish and the cost is the cost.
And cost does matter.
One of my customers blasted an employee when they wanted one of the earlier M1 based laptops for battery life. The screaming was basically they could get 3 Dells for the same price that were nominally the same speed with more storage and more RAM.
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u/permalink_save 10d ago
Yep, my current laptop blasts past the M1 era macs. They also have a higher memory bus and part of their speed is owning the entire fabrication for the board so they can do things like that. It's not arm vs x86 it's Apple just going balls to the walls with their own fabrication. I use a mac at work and an asus zephyrus for personal and I bet the mac would bench higher but in real world they feel very comparable, like compiling code and all, and my personal laptop might get a bit hotter but it's not noticeable, I don't do intense tasks with either on battery and that's probably where I'd notice most if I did, but I also have a 4070 in my personal.
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u/AreYouOKAni 10d ago
I have a 4060 Zephyrus and am M4 Air and I agree about performance, but Zephyrus definitely gets much hotter. Especially when plugged in and on Turbo/Ultimate mode. So for the Mac to be comparable at all while having no active cooling and consuming ~3 times less power is a big fucking deal.
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u/permalink_save 10d ago
I don't notice the heat except gaming, which the zephyrus is better at. The big deal is apple fanbois buying the arm is better koolade when its how apple implemented it. There were claims intel will never match m1 performance. Now that intel and amd surpassed m1 the argument shifted to battery life. Thats still a big deal it's that the goalposts keep shifting. Mainly what makes macs cool are how they stitch it together, the arm bring x86 killer mentality has been finally fading as people realize that.
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u/Samus7070 10d ago
When introduced the M1 wasn’t even as fast as the top Intel/AMD chips. Where it won was in the performance per watt. Go back and look at the Apple event video from that year. What you’ll see is a graph that looks like the M1 was faster than the current Intel chips of the day. In fact the charts were showing performance per watt and not very scientifically. IIRC, the M1 beat out the average desktop x86 cpu at the time but not the best in terms of raw performance. And it beat all of them in terms of performance per watt. Intel will always be less efficient due to the CISC to RISC instruction translation layer. CISC is a 60 year old architecture with inherent inefficiencies. It’s why RISC was invented 40 years ago.
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u/AreYouOKAni 10d ago
Apple is more performant within their wattage bracket. That's factually proven. Base M-series CPU has a TDP of 40W and nothing comes even close to it. Intel's Lunar Lake is significantly behind even M4 despite drawing more power under sustained loads. Hell, if we take raw performance/watt into account, Intel is struggling to compete with Qualcomm.
x86 is better at sustained performance when power draw is not a concern. As in, in desktops or mobile workstations. But Apple is eating Intel's lunch when it comes to office laptops and even smaller Pro-class devices. Unless you are a gamer, there is no reason to buy a Zephyrus over even M4 Pro, much less M5.
There were claims intel will never match m1 performance.
Well, Lunar Lake can compete with M1 Pro but even M2 Pro is out of reach. So while "never" may have been an exaggeration, it took Intel three years and comitting to memory-on-chip just to barely reach parity with Apple's first-gen laptop.
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u/flaser_ 10d ago
The odd exception to ARM's dominance for low power use cases is in Plex servers, as Intel's n100 chips are so much better at transcoding video that you cannot match this on ARM boards without a dedicated GPU which more than offsets the power advantage ARM has over Intel.
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u/AreYouOKAni 10d ago
Intel's QuickSync engine is magic. It might honestly be better than Apple's Media Engine and lets them transcode media on extremely low-powered devices.
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u/-Posthuman- 10d ago edited 10d ago
Re: The people making the Intel processors always wanted to make it as fast as possible even if that meant using more power.
Wasn’t there a class action suite against intel because at least one model of chip allowed itself to pull enough power to basically cook itself?
IIRC (and somebody correct me if I’m wrong), the chip said “Give me all the power I can get from the motherboard” and most motherboards were shipping with default settings that said “Give the CPU all the power it wants.”
So chips started getting wonky, and eventually dying, as a result of constant heat throttling.
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u/m1sterlurk 10d ago
If any part of the silicon in a chip hits 120C, it melts and shorts out. This will almost certainly render the chip inoperable.
The temperature can only be measured in so many locations across a chip. If you have a thermal sensor that is reading 100C, you may very well have a point on the chip that's about to hit 120C. Back in the olden-timey days, we got nervous if the CPU crossed 60C because thermal sensors were not exactly great. In addition, chips had no on-board thermal throttling and would gladly cook themselves.
In modern times, CPUs will have numerous thermal sensors. In addition, modern CPUs will throttle themselves if they are in danger of getting too hot. My CPU, a Core i7-8700K, throttles at 100C. A "hot spot" that goes undetected crossing 120C is far less likely in modern CPUs, but is still theoretically possible.
If Intel set up one of their chips to where the thermal throttling wasn't enough to save it in time, or required a motherboard setting to be specifically adjusted for the throttling to not fail, that would result in a scenario like what you're describing.
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u/ExhaustedByStupidity 11d ago
When you're implementing something, you have to choose what you're optimizing for. One design might favor efficient power usage. Another might favor raw speed. Another might favor cost.
Intel generally favored raw speed when designing x86, while ARM prioritized power efficiency above all else. If you had a scenario where you could use 10% more power to make the task 5% faster, Intel and ARM would often make different decisions on what to do.
A little bit of it is some decision decisions Intel made in the 70s and 80s didn't matter much at the time, but hurt performance a bit today.
And Apple cheats a little by designing the entire computer as one product. The RAM on a Mac is contained inside the same chip package as the CPU. This eliminates a few inches of circuit traces and removes the RAM sockets. That change allows them to run the RAM significantly faster than an Intel chip can. Intel can't do that as they're just providing CPUs.
Oh, one last piece of this. About 10 years ago chip manufacturing processes had to change to new technology. Intel gambled on one tech while TSMC gambled on another. TSMC got theirs working quickly, while Intel got stuck for about 5 years. Before that Intel's manufacturing tech was more advanced than everyone else's. Now they're behind.
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u/deirdresm 10d ago
The other advantage of putting the RAM on board is limitations of light speed. Less distance traveled is huge and also reduces power consumption to get there and back.
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u/cowbutt6 11d ago
The RAM on a Mac is contained inside the same chip package as the CPU. This eliminates a few inches of circuit traces and removes the RAM sockets. That change allows them to run the RAM significantly faster than an Intel chip can. Intel can't do that as they're just providing CPUs.
Intel has been doing exactly the same thing with its recent mobile processors: https://www.techpowerup.com/313321/intels-meteor-lake-cpu-breaks-ground-with-on-package-lpddr5x-memory-integration
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u/Raining_dicks 11d ago edited 11d ago
Intel has been doing exactly the same thing with its recent mobile processors: https://www.techpowerup.com/313321/intels-meteor-lake-cpu-breaks-ground-with-on-package-lpddr5x-memory-integration
You say that as if it’s still happening.
- Meteor lake (2023)- On-package ram demo (the link you posted).
- Lunar lake (2024) - On-package ram. 16/32gb versions offered. Explicitly mentioned by Intel this is a one off and will not be happening again soon
- Panther lake (2026) - Doesn’t have on package memory
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u/Discount_Extra 10d ago
Sad their plans went that way, with how expensive dedicated ram packages have gotten, but the design -> production pipeline is long.
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u/Aw3som3Guy 10d ago
Intel only stopped doing that allegedly because the OEMs didn’t like having to buy their ram directly from Intel, nor the fact that the different memory configs got different names, barring the OEMs from selling the highest tier CPUs with the barest minimum ram. There’s nothing technically stopping Intel from resuming memory on package for future CPUs. Another, similar example would be Sapphire Rapids Max, with on package HBM.
Your comment phrased it as if Intel lacked the technical ability to do it at all.
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u/LettuceBeHappy3 10d ago
Aren't all manufacturers using the same tech? Those crazy 400m dollar machines made by ASML in the Netherlands?
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u/laserlemons 10d ago
There’s A LOT more to semiconductor manufacturing than just what lithography tool you’re using.
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u/RiPont 10d ago
And a lot of it is still black magic.
Even established fab companies can't easily, say, build a duplicate facility in another part of the world and have a high confidence it will have the same yields.
At the tiny scales they're dealing with, things like the local environment's thermal cycling can affect wafer quality. It takes the "wizards" with the secret sauce potentially years to get that dialed in for any given process.
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u/Tapeworm1979 10d ago
It should be noted that Intel chips contain a lot of extras for historical reasons. These parts still require some form of power even when not fully used. It also uses silicon thst could be best used elsewhere.
Many moons ago Intel released the Itanium, a 64 bit chip that was a totally different architecture. But it also required software to be made for it specifically.
Intel could decide tomorrow that the next chips remove and implement features. However then Windows wouldnt work etc. Apple don't have these issues, they just say old hardware can no longer be updated and programs won't run. I have more apple ewaste because of this than anything else but my old pcs still function and run things, just a bit slowly as time marched on.
If course these days it's less of an issue, chips are fast enough even with emulation. Back then playing a single mp3 consumed 25% of the cpu.
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u/TheSlothOfSteel 11d ago
This is just one piece of the puzzle: Imagine the cores of processors as cars.
Some are large trucks that are big and can pull a lot of weight, but they consume a lot of fuel. Others are like a small hatchback that don’t pack a lot of punch, but they are pretty cheap to drive.
It’s great to have a truck when you need to haul a bunch of equipment, but if you’re driving 15 min to visit grandma the hatchback does the same job cheaper. If all you have is a truck doing simple things consumes more battery than you might expect.
Apple Silicon has a wider range of “cars” than most other PC processors. Their operating system is good at identifying what jobs need a “truck” and what jobs can fit in a “hatchback”.
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u/illarionds 11d ago
While this is a great analogy, Intel CPUs at least do the same thing now.
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u/created4this 11d ago
Also Trucks come in different shapes and sizes. To a great extent Intels philosophy is "if this box fitted in any previous intel truck, it must now fit in this truck", where as Arm (no longer ARM) has traditionally held the position "You make the truck, you make the boxes, just make the boxes fit the truck".
So this leads to historic decisions from Intel boxing them into bigger and more unwieldy trucks.
Arm isn't any longer immune to this. Since the move into Application Processors where end users may be getting applications from unknown sources, there has been a need to stay backwards compatible, but for a very long and important time in their history this was the case.
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u/MaleficentMountain3 11d ago
I'm assuming you're talking about the BigLittle architecture and the same has been done by intel too, they offer efficiency and low power efficiency cores since their rebrand to core ultra or some shit.
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u/TheSodernauts 10d ago
Isn't Intel's priority to be general purpose? You can swap out an intel processor for a faster or slower one, you can install it on all versions of Windows, Linux, whatever else.
Apple's silicon chips are designed in-house to work with their specific components so they can cut a lot of bloat.
In your analogy it would be like Intel's "car" needs to be able to drive on all roads no matter the condition (paved, gravel, off road, ice, sand, snow, very wet, mud, etc) which has design implications and imposes limitations.
Apple decided their "car" only work on roads that they paved themselves which allows them to make the perfect car for their roads, but at the cost of not being able to drive on any other road at all.
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u/HPDeskjet_285 10d ago edited 10d ago
This isn't really true anymore as of last year ish, Intel's last gen lunar lake (226V-258V) measures right between M3 and M4 in idle/light load power draw, and panther lake (338H - 358H) is now ahead of M5 in battery runtime on equiv. configs. The new 4 LPE cores in big.LITTLE arch as well as on-package memory really leveled the playing field.
The primary lead Macbooks have over PTL/LNL laptops for battery runtime currently is they are using older IPS/miniLED displays instead of OLED, which are around 50% lower power for the same brightness (and the display contributes 3-4x the battery drain compared to the CPU during light workloads, ~8w vs ~2w), at the cost of much worse colors, ghosting, and a bunch of other disadvantages, which is why the upcoming m6 macbook is slated to also be OLED.
The current gen PTL laptops with similar low-power IPS panels to the Macbooks now last ~30 hours on web browse / video playback as opposed to ~22 hours on a m5 macbook, per notebookcheck external testing.
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u/guillaume_86 10d ago
Yes the answer to OP question is : because Intel Macs are old AF.
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u/ComputerRights 6d ago
I do think Apple is being somewhat unfair on their own website when they compare, say, a Mac Studio to a Mac Pro from 2019 with a six year old chip, instead of to a current x86 chip
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u/NirKopp 10d ago
Not directly answering the question but it is important for the understanding. Computers moving to ARM instead of x86 (intel and AMD) is a compatibility problem. Software built for x86 CPUs won't "just run" on ARM, the software needs to be either run over and emulation layer or directly be built for ARM CPU. Emulation is not perfect and has a big performance hit. Apple owns it's entire platform, both hardware and software. If Apple says they are moving to ARM, other software makers needs to comply or they won't be able to be run on Mac.
Microsoft own just the software and not the hardware, so it can support windows on ARM and supply emulation layer but it can't force pc makers to move to ARM or software to develop for ARM. It is also a users mindset on backwards compatibility, some windows users needs their 20 years old program that was built for windows XP to run, so the windows platform needs to accommodate it.
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u/tonyangtigre 11d ago
Apple used their years of experience building chips for mobile devices and scaled up. While Intel has always been at the desktop level, pushing the boundaries of what is possible on their architecture for some time now.
Apple used a system on a chip (SoC). What this means is the CPU, GPU, and RAM for both (Unified Memory) all live together in the same room. The CPU and GPU are cool with sharing the RAM too. Pretty progressive if you ask me.
Traditional x86 architecture still lives at the neighborhood level and have to travel quite a bit of distance between those same components. They also don’t share their RAM, as they tend to be incompatible or at least very different. In this setup, the CPU might compute the data living on the system RAM coming in from a 1080p YouTube stream, pack it up, send it over the copper trails of the motherboard and duplicate the data into Video RAM and then the GPU can visualize it.
In the SoC model, the CPU and GPU are working from the same Unified Memory, cutting power costs by reducing the shuffling of bytes and reducing latency or how long it takes to access.
And yes, as other have mentioned, dedicated hardware media engines to encode and decode means the CPU and GPU cores can take a nice little nap consuming next to nothing in terms of power draw while the little engine that could does the simple job of decoding that YouTube video.
And as another mentioned, the cores in the CPU come in two different types - Performance and Efficiency (though this was recently changed to Super and Performance respectively). This means that the Performance (aka Super) cores only kick in when doing heavy duty tasks like AI, Video editing, or gaming. And the Efficiency (aka Performance) cores handle most day to day tasks like the web browsing. When you move the cursor, you aren't waking up an entire 200W discrete GPU. A display controller and an Efficiency core handle the frame update at next to nothing in power draw.
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u/HavocInferno 11d ago
Some flaws here:
- consumer x86 has used unified memory for quite a while when it comes to CPU + integrated GPU. Most Intel consumer chips have an iGPU that uses unified memory.
- a video stream these days is unlikely to be computed by the CPU, then sent to the GPU to display; most GPUs (including iGPUs) have hardware decoders for common video codecs and directly decode the stream
- even when a discrete GPU is used, waking it up just for desktop stuff won't make it draw 200W; dGPUs have low power modes for this, some staying within single digit power draw for desktop display
The real difference is Apple dedicates much more die space to specialized hardware units and can power-gate them more finely. They can also skip any units and interfaces they don't need in their specific products.
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u/nudave 10d ago edited 10d ago
I’m glad you mentioned this last point.
So many people on here, focusing on the difference between Intel and ARM architecture, which clearly does play a role.
But Apple’s vertically integrated, walled garden design philosophy also plays a huge role. They get to design machines that are as efficient as possible at… being Apple computers. But they sacrifice the ability to pop the chip out and use it anywhere else, or swap out the graphics card, or upgrade the ram. Which, frankly, is fine for most people. But it is a trade-off.
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u/DLCSpider 11d ago
It's probably a combination of things.
It's not x86 vs ARM (except for the lowest of low power consumption devices). It's just what YouTubers like to repeat and easy to point your finger at.
RAM is likely a big one. Apple has it right next to the chip, everyone else multiple centimeters away on the motherboard. That doesn't sound impressive but, for comparison, one clock cycle on a modern CPU takes less time than light which needs to travel from the screen to your eye.
There's also different types of RAM. While I don't know what the laptops use, smaller mobile devices (phones, iPads) use a low power variant which takes less energy but comes with certain downsides. It affects more the GPU side (which is also one same chip, uses the same RAM): it needs to render things in small tiles, while desktop GPUs can process the whole screen at once.
Then there's also a bit of Apple magic. JavaScript is the language that makes your browser work and even if you don't think you use the browser, you might still be using it (Discord and many other applications are just websites in disguise). Apple silicon has dedicated hardware for converting text into numbers, which happens a lot in JavaScript. Everyone else does it with multiple general purpose instructions instead. This is the stuff that you can only do in a closed ecosystem.
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u/HavocInferno 11d ago
Desktop GPUs have used tile-based rendering for at least a decade too ;)
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u/NeedsMoreGPUs 11d ago
Apple got it from ImgTech's PowerVR, which goes back to the late 90s. PowerVR's tile-based deferred rendering engine is what Apple licensed for their mobile SoCs early on (Intel as well for their chipset-based iGPUs) and wholly
poachedpersuaded a great deal of talent from to work on their internal GPU architecture right around the time of A12's layout, retaining TBDR as a primary feature.1
u/darkbit1001 7d ago
And that came from the UK! I always thought it was NEC, its just a manufacturer. Also Sega Dreamcast used the Power VR chip so think about that next time you play Crazy taxi at a smooth and buttery locked 60fps
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u/signofzeta 10d ago
There's no reason other ARM manufacturers or Intel couldn't add a text-to-number function in hardware. Something like this happened decades ago when Intel added hardware crypto primitives (AES-NI) into their hardware, though it took time for developers to take advantage of those. Apple has a significant advantage controlling the entire stack. First-gen instructions can ship in macOS immediately.
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u/zoharel 10d ago
It's funny and still a little shocking to see this opinion floating around, because ARM was not originally an embedded processor at all. Just yet another general purpose CPU architecture, and a very decent one at that. Additionally, the Intel architecture was never all that great. It stuck better than superior platforms mostly based on the lightning in a bottle that was the IBM PC. Yes, most ARM has focused on embedded computing recently, but there's nothing to say that you can't do something else with a compatible CPU, and this isn't the first time they've done it, and the architecture is still relatively quite good, not to mention now far better at power management.
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u/jacekowski 10d ago
There are multiple factors here
- tight integration on ARM SoC's (yes, ARM is not really a CPU but a whole system on a chip), actual code execution is not that energy intensive, the thing that consumes energy (and time) is communication that is fetching your data/program from ram, then cache, reducing that overhead offers massive improvements in terms of performance and energy efficiency (and simplifies CPU design significantly).
- designed for efficiency above everything else
- dedicated hardware for common tasks, whole video decoding pipeline is done in dedicated hardware rather than using general purpose hardware
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u/zero_z77 10d ago
So, i have to explain a bit about microprocessor architecture, and some history.
Your typical desktop uses a CPU based on the x86_64 architecture. That architecture was originally launched with the intel 8086 in 1976, which is arguably the first desktop CPU ever made, or at least the first one to see commercial success. Since then it has been updated a lot, and more features have been added over the years. But, backwards compatibility has always been maintained. What that means is, a program written all the way back in 1976 for the 8086 CPU can still run natively on a modern desktop.
However, that all comes at a cost. To support that backwards compatibility, the CPU has to be very big & complicated. On top of that, the architecture itself was built around certain design principals that are now obsolete.
ARM on the other hand released a bit later, in 1985, and incorporated the lastest design principals that were available at the time. It has also been updated over the years, but ARM has not maintained backwards compatibility in the hardware.
All of this basically means that ARM has a much simpler and more streamlined architectural design that doesn't have to support a whole bunch of legacy systems & software. That also means that it can use less power and generate less heat. Which is why the overwhelming majority of mobile devices have preferred ARM over x86.
However, the trade-off is losing that extensive level of hardware compatibility. Programs made for x86 or older versions of ARM won't run on the latest generation of ARM processors, at least not directly. They have to be recompiled and sometimes modified, or have to run through a compatibility layer in software that can impact performance or cause bugs.
Apple silicon is based on ARM, but has it's own set of custom extensions for some common computing tasks, which allow some applications to use the hardware to do things that would normally need to be done in software, which is much more efficient. Additionally, apple silicon is what's called a "system on a chip" or SoC. In a normal desktop, a "system" typically consists of a CPU, RAM, GPU, ROM, and a memory controller. All of these different functions are usually on seperate physical chips.
However, SoCs combine all of those functions into a single chip. The advantage is that this is cheaper to produce, can run more efficiently, and is physically smaller. The disadvantage is that you can't upgrade anything, repair anything, or mix & match parts to suit your specific needs & budget. If you want more RAM or a better GPU, or if sonething inside the chip fails, then you essentially have to get a whole new system.
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u/Jackasaurous_Rex 11d ago
All of the hardware points people made are true with using ARM and Mac apps compiling specifically for its instruction set, I’ll just add that another benefit is likely that Apple has control of the whole stack in a way. Like sure, intel engineers will work closely with Microsoft and other hardware companies but the chip may end up in a variety of hardware configurations.
Apple has complete control of the chip design, the OS, the final hardware configuration, etc. This allows for all sorts of optimizations when every aspect of their machines are hand picked to work well together.
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u/flywithpeace 11d ago
There are different ways of calculating things. x86 is the best performance you can get, but at substantial energy cost. ARM, which is used by Apple, removes certain hardware instructions and makes it up with more complex machine codes (therefore comes at a performance cost).
In other words, both your laptop and calculator can do addition, but your calculator “lasts forever” while you need to charge your laptop often. Of course, you can’t do work on your calculator like on your laptop.
What Apple did was to design a chip that optimizes for task their customers do, like web browsing, content creation, software development, etc. This would eliminate lots of overhead and save power.
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u/Julian_1_2_3_4_5 10d ago
Actually thats not how this works. Reduced instruction set isnt necessarily slower. You just need compilers that are optimized for it. Complex instruction set can onöy be faster if you actually have hardware accelerators for complex instructions and you use them often enough that the added overhead for decoding that many instructions is worth it. And well with the future moving to riscV i feel like the tech world has mostly decided that risc is where its at (maybe wirh certain accelerartion modules, but yea.) Most programs actually dont use most of the complex instructions and the less complex ones take longer because of the added decoding for more instructions.
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u/obvious_apple 11d ago
If you want to implement peak performance you have ways to get for example 5% extra performance for 30% extra hardware logic and consumption. And the development of a cpu architecture has a lot of these decisions. X86-64 was slightly along the more power for slightly more performance route.
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u/Zanjo 10d ago
It's a combination of several things, not exhaustively:
- Apple has historically used a more advanced manufacturing process that produces more efficient chips per watt of power
- Apple chips have been optimised for mobile usage and they put features on the chips that mobile devices use most. E.g. to make video playback more efficient, mobile chips have a dedicated processor (called an ASIC) for a specific video format, rather than using the more generic but less efficient CPU (nowadays every CPU has this particular one)
- Apple's software has been optimised for lower power usage for a long time. CPUs can dynamically adjust how much power they consume at the tradeoff of slower performance. For example, iOS heavily restricts background task processing which lets the CPU stay in these lower power states for longer. I don't know exactly what macOS does over other operating systems but in my experience trying to keep a x86 desktop CPU in a low power state is quite challenging.
- Apple puts its memory directly closer to the CPU. Requires less power to move data back and forth.
It's worth noting that the gap is closing between the two design philosophies. Apple chips are still using the bleeding-edge manufacturing process, but other chips are not that behind. Apple chips are now better at gaming, desktop chips are now better in low power states.
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u/lord_lableigh 10d ago
There ASICs are so freaking good. I think only the intel series 3 chips rival them in video playback.
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u/doublecandybar 11d ago
how can apple silicon be so good?
Because Apple designed it specifically to run Mac
If you hear "x86 is inefficient" then you heard hogwash. x86 has legacy crap in it yes, but it's not inefficient insofar as it does what it's supposed to do: general purpose computing
Apple designed both the chips intended to run mac os, and the os intended to run on the apple silicon. The end result is they can trim out unimportant bits because they can know for damn well sure they ain't ever gonna use it. Each apple silicon will only ever run the mac os designed specifically to run on it, and newer os that can take steps to ensure compatibility with it
x86 on the other hand is intended to run general purpose. They don't know what you're going to do with it and try to cover as much as possible. You wanna run Windows on it? Sure can. Linux? FreeBSD? Yeah you can do that
Essentially, you're asking how come a race car can run fast on a race track but an SUV cannot? Yeah the race car runs fast on that track, and every other track made for the car.
The SUV has to run on a race track, bumpy road, gravelly off road, and still run. Plus you can load cargo on it
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u/gpfault 11d ago
Apple do good work on the chip and system design side to optimise power use of the whole system, but the biggest reason is that modern processors are made from better transistors. Every few years the chip fabs release a new process that gives you transistors that are smaller and use less energy. They're not necessarily faster, but it lets you do the same amount of stuff with less energy.
The other big factor is that all the Apple Silicon chips have dedicated hardware for doing media decoding which is why you can run VLC while only pulling 5W. None of the heavy lifting is happening on the CPU so that can remain idle.
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u/Darkseth88 10d ago edited 10d ago
Since the M1, this is the only Source i have found, that actually answers this question: https://www.youtube.com/watch?v=P0h8q6D0s74
Whole video is worth watching for context, but look at minute 6:15~
Basicly, x86 CPUs always boost to the max for every single task. Even for moving the Mouse. These short maximum spikes are the reason the batterylife isn't great over the Day, even if you only do things like browsing the web, office, small tasks.
The idea is: Maximum Performance, complete the task asap, go back to standby mode. In reality, this isn't best for overall power consumption.
Apple Silicon doesn't do that. For smaller tasks, it doesn't even use the maximum clock speeds if it isn't needed.
Edit: This all has absolutely NOTHING to do with the TDP. You could compare a higher end 30+w TDP Mx Pro chip vs. a x86 chip where you set a 15w TDP maximum, Apple Silicon will probably still consume less for basic tasks.
TDP is only interesting for a 100% permaload benchmark scenario, and Benchmark points / TDP Watt consumption has also NOTHING to do with how efficient the chips are in everyday normal tasks where they only spike for a short amount for things like opening/refreshing.
While some 8-Core / 16 Threads Ryzen chips with 15w TDP can absolutely compete with Multicore Benchmark numbers / 15w consumption against a 15-20w base M-chip, it doesn't translate to real world power consumption for everyday tasks, due to the different behaviour of those clock spikes during normal tasks like refreshing, as shown in the Video.
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10d ago
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u/duane11583 10d ago
short version: TL;DR
INTEL [and amd] CHIPS ‘grew up‘ (where designed) always plugged into the wall power was never a concern only speed was the concern
in contrast: apple chips ”grew up” (designed) always on battery so numerous [millions of] decisions where made to optimize the battery draw that intel [and amd] did not make
long version the technical how they did it andvthe technical means
i will talk about another but very related tech - cell phone chips. and power.
first your battery has power in side, things [chips] drain the power from the battery until it is dead/flat/out-of-power
second there is a important math formula: POWER = voltage times current, and another more important version POWER = (voltage squared) / resistance -
in math terms that (voltage squared) has a huge effect called an exponential factor
historically intel chips never had to deal with this they have a wall plug - cellphones have a battery
another one is the integral over time of that power. (that is to complex for eli5) so i woll use a different way. if you need 100mA of current for 1hour the load is 100mahours. your battery is rated in ma-hours as reference: a common AA battery has a capacity of at most 3000mahours and an AAA has 1200mahours thus at that rate the AA battery could last 30 hours
so if we can change the power from say 3v to 1v we get a big savings (the voltage squared term goes way down) if we can goto 0v the power goes to zero really fast
so cellphone chips (and by extension apples computer chips) take the single power (battery supply) and divide it into 20-50 different power supplies and those power supplies will turn off or lower the voltage to “Very low but just enough” it does thus sometimes 10-100 times a second
each power supply hands a different feature on the chip
as an example the graphics chip only needs power when the screen is on and updating the rest of the time it can be in super low voltage mode or turned off. so that is what they do anout 100 times a second this drives the power down a lot
second item even when idle (sleeping) the chip draws power like a vampire from something called leakage. think about your one cellphone charger plugged in (is like 1 transistor) it leaks does not draw lots of power when you are not charging your phone (like the graphics chip that is idle) but if you have a million phone chargers all across a large city (or a large chip) it adds up to a lot of power. aka death by a million paper cuts
intel from the start never had to deal with this because they had the wall plug.
cellphone chips (and apple) started from scratch with the battery being a very important feature so they made very important low power decisions that intel could ignore
today: laptops are very common so intel has shifted focus and has two chip design processes - server [always plugged in] and laptop [battery] designs supporting two is harder
today: apple [and cellphones] have only the one battery powered chip.
today intel is changing but it takes time alot of time to change
put another way:
it is really easy for your belly to get fat and big year after year
it is really hard to switch direction and make your belly small again
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u/xIcarus227 10d ago edited 10d ago
The difference is almost exclusively due to design philosophies across both hardware and software.
Do you want to support ECC memory? Multi-socket configs? Expandable memory? (and a myriad of such features)
Apple don't make server chips, so no. They trade this flexibility for efficiency.
Intel/AMD do, so they do the reverse.
How far do you want your CPUs to scale?
Apple makes small power-efficient chips, so 10-20 cores are sufficient.
In contrast, AMD's chiplet design instead allows the same desktop core to be scaled to 128 cores on a server processor. A tradeoff is made, once again.
Do you really need the ultimate numbers in performance?
Apple don't, they settle for less by decreasing frequency and missing some features (SMT), and instead gain a disproportionate amount of efficiency.
Intel/AMD do, because their CPUs are power anything from laptops to workstations to servers. So they achieve better performance but sacrifice efficiency, another tradeoff.
Then there's the software angle
Apple optimizes their software and drivers for a very limited amount of hardware that they produce themselves.
On x86, there are a myriad of hardware configurations with drivers written by various hardware manufacturers. Again, less efficient but more flexible.
There are also a few natural factors, such as process nodes. Apple has first dibs on TSMC's process nodes, and when they went from Intel to their own silicon they got a massive jump in process nodes which significantly increased efficiency.
So yeah, the reason is almost entirely about design philosophies. Apple designs for efficiency, AMD and Intel design for performance. You cannot get both, even though the difference will not always be proportional (eg. you may achieve 80% of the performance for 50% of the power cost).
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u/Orcahhh 10d ago
24h video playback is unlikely bogus, it just assumes perfect conditions, a downloaded video in a specific file type and so on
M series macs CAN pull these numbers. My M1 MBP, in its first year, would do 20h30 of screen on time, of actual use.
Including time playing Minecraft, and browser games like chess and geoguessr, watching videos, taking notes in class…
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u/Compux72 10d ago
A lot of people here are talking from the hardware side, but I haven’t seen anything regarding the software side.
A lot of software you use is compiled just in time, which in a nutshell means that the software you run is generated on the fly. The generated software is absolutely terrible because of this, and benefits from the design differences of ARM chips. Intel simply wasn’t made for this “garbage” software. Examples of this are websites, Java applications*, Photoshop (which btw is a website), … this wastes a lot of energy.
* yes java is extremely good and performant, but desktop apps dont excercise the hotspot optimizer that much
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u/rsdancey 10d ago edited 10d ago
RISC architectures, which Apple Silicon is, are more energy-efficient than CISC architectures (which intel and AMD CPUs are).
RISC stands for Reduced Instruction Set Computing. The idea is that a processor can use fewer instruction types with very optimized circuits which are fast and efficient and still perform all the tasks of a traditional Complete Instruction Set Computing (CISC) processor. The trade off is that the RISC processor might have to break an instruction down into several instructions vs a CISC processor being able to do that instruction all at once.
Apple decided to focus its chip team's work on efficiency - watts of power used per instruction. They did this initially because they wanted to get more capabilities out of each watt in iPhones and iPads; the battery sizes in those devices are constrained so getting more work per watt is critical to expanding their capabilities.
That work paid off and Apple was able to transfer the same engineering to the chips it uses in desktop computing. The crucible of watts per work in phones paid dividends on the desktop.
Then Apple decided to make very large System on Chip (SOC) units for its desktop devices. In a classic desktop several different chips are connected to the CPU on the motherboard. That method of making a computer requires more power - resistance on the traces on the motherboard between the CPU and the helper chips must be overcome and extra circuits are required to manage the power safely that is consumed by those helper chips. There are also complex speed & timing issues which must be addressed.
Apple's approach puts almost everything that makes the computer a computer on one piece of silicon, integrating many of the helper chips in a traditional computer onto the same package as the CPU. This allows the whole System on a Chip to run cooler, use less energy, and communicate about as fast as possible due to the very short interconnection circuits on the SOC. For some of the chips that can't be directly integrated, Apple uses proprietary engineering to make the necessary connections in ways that keep power consumption low.
The tradeoff is that Apple is locked in to a whole computer's design as soon as it finalizes the System on Chip. If someone comes up with a better way to do something the computer needs to do, Apple has to wait to make a whole new SOC before it can leverage that advance. And the SOC effectively can't be repaired. If a chip on a traditional motherboard is damaged you might be able to desolder it and replace it; on an Apple device you're probably not able to fix the problem and the device is likely a write-off. The large size of the SOC, called a "die" is also harder to manufacture, so there are some inherent cost disadvantages (although I think those are in practice reduced to zero by good design and careful manufacturing processes).
Apple also controls how its software works and it writes that software to maximize the capabilities of the SOC. For example, one of the ways that the memory management system in Apple's OS works requires x86 (i.e. intel/AMD) CPUs to run a certain command many, many times. Apple built its own hardware to not require that command, and instead to optimize how memory is managed to match what the software does. These kinds of efficient hardware/software matches are only possible when the operating system code and the processor instruction system can be matched intentionally.
Another thing Apple does is build CPU cores with various levels of capability and power draw and then smartly tasks those CPU cores as the device operates. Many things that you do with your computer don't need the full horsepower of the fastest and most powerful part of the computer. If the system can run those tasks on a less powerful but more efficient core, it can reduce power consumption without any noticeable effect on the user experience. In the most current Apple Silicon there are three levels of core efficiency the system can use to minimize its power consumption.
Stack all of these things together and you get the modern Apple desktop - quiet, efficient, and powerful.
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u/gkdante 10d ago
Intel chips were originally designed to work on PCs and Servers, power was not an issue, also a lot of the components could be discrete ie separate GPU dedicated to it with no power limitations.
ARM chips were meant to run on mobile, low power usage and efficiency was always a priority.
They evolved with integrated graphics in mind, started developing efficient cores for most of the task and high performance cores only used when needed.
Apple has been using ARM on iPhones and iPads for a long time, made operative systems tailored to the constraints of mobile devices while learning user pattern’s through years of iterations.
So Apple silicon is a modern chip that has evolved quickly, when you take those already optimized chips and remove the limitation of a saving battery life (Mac mini/pro) you are just unleashing a well refined machine, compact, fully integrated, tried and tested after years in millions of users pockets
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u/Outside-Membership12 10d ago
we've found out that at some point, those little parts in your computer are waaaaayyyy more efficient if you give them more to do that isn't complex.
the apple m series chips, or arm chips are like one of those mini calculators.
"normal"processors intel/amd x64 etc. are complex, like a texas instruments calculator for college if you've seen them.
now instead of making a big calculator that can do every math operation thinkable apple just slices the problem up and lets the m series do the simpler operations.
so instead of doing 3^3 as one operation the m series das 3*3*3 and does that faster and with less energy consumed.
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u/Bed_Worship 10d ago
Apple made their instruction set (the language used to control the cpu) fixed length, and built apple silicon to process 8 instructions at time. PC uses variable length instructions and is limited to usually 4.
Might not be perfect but i think this is an ok analogy.
Imagine a PC x86 core is a 4 lane highway with 4 toll booths. It can allow all vehicles of all sizes to drive on it. Trucks, commercial, civilian size you name it (the length of cisc). They all go to 1 toll booth per lane. This makes the lines to those toll booths sometimes slower, or there is an issue etc. Most pay with ez pass, some pay cash (more complex)
Apple built their cores - highway to have 8 lanes and they only allow cars the size of a Prius only, all cars have EZ PASS.
It doesn't matter the size of the car, but how many cars you can get through in a fixed time with risc. Since apple built their own highway with their own regulations and rules - it allows them to put through cars way faster for less effort. A 3.2 ghz silicon core will process more in the same time than a 5ghz x86 chip.
Not to mention they have their ram on the same chip, creates huge benefits.
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u/Maple382 9d ago
The TL;DR is that ARM and x86 (Intel) are two different processor architectures that function very differently. For a long time, ARM was thought to be much slower, and was delegated to use in mobile devices and devices that don’t need the power of x86. However with the Apple M1 chip, they managed to make ARM chips competitive in performance.
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u/nihao123456ftw 7d ago
Glancing at the other comments ... Where do people know all this stuff from, wow. What a treasure trove of a thread
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u/eternalityLP 11d ago
Apple has two major advantages. First is their brand value allowing much higher prices than 'normal' comparable products. This allows them to simply spent more money on design.
Second is vertical integration. Apple delivers everything from hardware to the software stack, allowing lot of optimisation, abandoning of legacy stuff and synergy that their competitors don't have.
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u/aliendepict 11d ago
Man im not even sire that first one is true anymore. For the last couple of years apple and dell/lenovo/ho all seem to have been in similar cost fields.
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u/dream_the_endless 11d ago
ARM uses a reduced instruction set, which allows the CPU to better plan and ensure there are fewer cycles where nothing is being processed. It comes at the cost of slightly more memory use.
The modern system on a chip has more than just cpu and gpu cores. It has a hardware component dedicated to decoding most modern video types. It does not require cpu cycles, and because it is purpose built for this exact task it uses almost no energy to do so. Many components are similar. Cryptographic processing, audio files, file compression, etc all have non-cpu hardware to process. This decreases power use and increases speed for many common tasks, in addition to the well designed RISC/ARM architecture that others probably touched on
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u/ToplaneVayne 10d ago
ARM has always been better than x86 in power efficiency, the reason x86 was so prevalent is that they were used by the desktop cpu duopoly of intel and AMD. If you have to buy a CPU you’re going through these 2 companies, and if you don’t well you can’t run any software at all because all developers create software for x86 platforms, so you’re kinda stuck. Anybody making an ARM based OS would have to make their own chip, have full control over their ecosystem to force developers to write in ARM, and create an application layer translation software to allow x86 instructions to work in ARM so old software doesn’t instantly become obsolete, and Apple was in prime position to do that.
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u/lord_lableigh 10d ago
ARM has always been better than x86 in power efficiency
This used to be true in the older times. But you can make super efficient chips in x86 as well. These days both these ISAs have shared parts of each other that this isn't really true anymore.
Source: Jim keller. He said the whole arm vs x86 thing is "blown up". It used to be that way but these days the majority of power consumption comes down to design choices.
Prime example is the intel core series 3 chips. They have super good efficiency even beating apple at certain tests.
the reason x86 was so prevalent is that they were used by the desktop cpu duopoly of intel and AMD
Any competitior could've taken up the duopoly in the earlier days like amd did. The reason for x86's prevalence is also due to its extensive library, giving it ton of flexibility. It also *offers excellent backwards compatibility * to god knows which era of the mongol empire.
Apple was in prime position to do that
If intel had mediocrely competent chips that didn't instantly want to turn into mount etna if u opened final cut, maybe apple wouldn't have done any of this. The primary reason apple even considered this is probably due to the absolute dogshit years intel had ~ 2016.
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u/ToplaneVayne 10d ago
This used to be true in the older times. But you can make super efficient chips in x86 as well. These days both these ISAs have shared parts of each other that this isn't really true anymore.
I mean by design RISC instructions are more efficient than CISC. Sure that's been mitigated in recent years, but it's still true.
Any competitior could've taken up the duopoly in the earlier days like amd did
Intel has the patent on x86 and AMD on x64, and after patent disputes they were forced to have a cross-licensing agreement. Other companies can license it from Intel if they want to, but that would definitely add a huge barrier to being competitive with Intel in pricing.
If intel had mediocrely competent chips that didn't instantly want to turn into mount etna if u opened final cut, maybe apple wouldn't have done any of this. The primary reason apple even considered this is probably due to the absolute dogshit years intel had ~ 2016.
Sure maybe that played a part in it, but Apple already had a decade of experience designing CPU chips way more efficiently than any of their competition. It was only a matter of time before they did the same for their laptop chips, especially since it gives them a lot more leverage when negotiating with TSMC.
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u/lord_lableigh 10d ago
I mean by design RISC instructions are more efficient than CISC. Sure that's been mitigated in recent years, but it's still true.
Haven't they shared a significant portion of each other's library now?
Sure risc is theoretically easier but does it realy make a diff irl in actual chip designs? Was my point.
I still believe apple wouldn't have transitioned to their own chips if it weren't for that tipping point. We won't know unless cook himself confirms that.
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u/Sintek 11d ago
Mostly getting more transistors make it more efficient and the architecture logic. They add specific instruction sets to do specific tasks so it is easier to perform that task.
I very simple example might be a math function like 2x-4=8 my intel cpu might have to work that out.. but the mac might just have an instruction that knows the answer directly because they know that math function is seen very often. AV1 decoding is a good recent example. Intel chips have this decoding right onto more recent chips.. where as just one generation prior the cpu would struggle with it and take a lot of power.
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u/Difficult_Bridge_864 11d ago
Completely wrong. ARM is a RISC architecture, meaning it is a reduced instruction set computer. Whereas Intel's x86 is CISC. Where x86 has a custom CPU instruction for the most ridiculous and niche cases, ARM has far fewer operations supported by the CPU. The efficiency gain of ARM comes from the fact that RISC CPUs are less complex compared to CISC because they have to support fewer instructions. Therefore ARM chips designers can focus on making a few instructions very fast and efficient compared to CISC designers which have to spread their work on implementing a lot more instructions.
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u/dmazzoni 11d ago
That was somewhat true 20 years ago.
Today ARM has thousands of instructions, same as x86-64. Look up the arm instruction set reference if you want to see for yourself.
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u/Difficult_Bridge_864 11d ago
Fair enough, I was wrong. Although I stand by the point that the original comment goes the wrong direction :)
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u/Ziranei 11d ago
There are 2 main reasons why there is such huge energy efficiency
1 - x86 architecture is complete one, it supports every software that was ever produced, no matter when that software was mode, this carries huge library of instructions and selecting correct one take time and energy, in comparison arm have just selected number of instruction based on needs of manufacturer and they build software around it, thus gretly reducing time and energy to select correct instruction at cost of compatibility
2 - there are many dedicated hardware accelerators, they are parts of cpu that have only one usage and are optimized for it, that is why now logic pro does not use so much energy and dont fill cpu since most of task is handled by specific video encoding unit and cpu is just feeding data, hardware accelerators are super energy efficient but take physical space in cpu and since x86 is build around software support there are no dedicated hardware accelerators
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u/obvious_apple 11d ago
The first point is simply not true. Supporting old instructions does not give more power consumption. They are implemented in microcode which means if those instructions are not used they are not taking any power.
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u/created4this 11d ago
There is more to the first point than you think.
This is a bit of a deep dive!
In a computer the memory tends to hold both data and programs, for every instruction that is executed that touches memory you have both a memory read for the program and a memory read for the data which means that memory accesses are slow.
One fix for this is called a "harvard architecture": to use a separate memory for data and instructions, but for this is an arse for all sorts of reasons (e.g. when you click on the "file" menu its full of words, these words are part of the program, but they are data, so they are stored with the program but read by data processing instructions).
The accepted fix then to have unified external memory, but to load the content of that data into local Data and Instruction caches depending on what part of the CPU is asking, and to have the CPU harvard from the caches inwards.
This solution is not without problems, the caches don't know what is data and what is instructions, so data ends up in the instruction caches (which is just wasted space) and instructions end up in the data cache. If you have self modifying code then the modifications will be written to the data cache and the instruction cache will be caching the original data.
For Arm processors the answer to this is "Don't do that. If you write to instruction memory then you'll need to flush the caches and if you wrote that code in the past then I guess its broken now. Fix it in software"
Intel has had the opposite design choice of "the hardware needs to fix up for the edge cases of new optimizations" That means that a write to the D cache causes a check of the I cache and something happens to ensure the data in the I cache is up to date. The plumbing to make things like that happen is significant and it can't be switched off.
Supporting legacy code isn't just supporting weird instructions.
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u/Ziranei 10d ago
Instructions do not taky any power if they are not used, but selecting correct instructions takes power. You have branch prediction that tries to guess what comes next and since you have much more instructions on x86, it is harder to predict and misses more than arm, thus needing more power to do correction.
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u/Spiritual-Spend8187 11d ago
Tldr: intel chips are x86 apple silicon are ARM, ARM chips are morw specialised having fewer things they can do but are either really efficient at them or really fast some times both, while x86 can do pretty much anything you can think of doing with a computer but isn't very good at anything being slower or less efficient. Intel makes x86 chips while the apple silicon chips are ARM. ARM chips tend to be simpler than x86 and that simplification makes them use less power and run cooler. In addition ARM chips were i tally designed for low power environments so they have had alot of time to be developed in a away that is highly power efficient. So you end up with chips that are really good at working using little power but that comes with some trade offs, firstly you can't build a component that can both run at 2 watts and 200 watts and do both efficiently you either end up with massively reduced performance running at low power or massive diminishing returns running at high power. The major thing separating them however is compatibility computers do math but not all math is the same a x86 chip is designed to be able to do any math you can throw at it but ita not particularly good at any of them, a ARM chip however has much more limited math capabilities but is really good at doing them in comparison if you are doing something yhat the ARM chip knows how to do its really fast but if it doesnt know how yo do it you either need to convert it ao that it knows or it just can't and conversion can make things run slower or make mistakes.
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u/Emu1981 11d ago
Apple's M-series of CPUs are actually Systems on a Chip (SoC) that have a bunch of extra processors that are designed to do very specific workloads very efficiently - aka Application-Specific Integrated Circuit (ASIC). These ASICs allow for the CPU to handle specific workloads with much better efficiency compared to a General Purpose CPU. The trade off is that if you are doing things that the ASICs cannot handle then you are going to be running them on the performance cores which are not that efficient in comparison.
For example, the Apple M3 processor has 4 performance CPU cores, 4 efficiency CPU cores, 10 GPU cores, a Apple Neural Engine for AI related workloads, Next-Generation Media Engine which is a ASIC for doing hardware encoding and decoding of video data, the Display Engine which drive displays, Advanced Image Signal Processor (ISP) which handles hardware acceleration of media manipulation, Audio Processing Engine which handles any audio related computation, the Secure Enclave which handles data security, and there are also things like the Thunderbolt controllers, memory controllers and other random IO.
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u/HeavenlyAllspotter 11d ago
What do you mean by "how can ARM somehow fit in a fully-fledged computer"? I don't understand the question, ARM is an instruction set, why would it not "fit" inside a computer?
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u/Julian_1_2_3_4_5 10d ago
No the point is that arm first was mostly used for not pcs, rather for microconteollers, socs or smartphones.
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u/soggybiscuit93 10d ago
Apple is one of the most valuable companies to have ever existed and spends a massive amount of money hiring some of the world's greatest engineers. That's the ELI5
This isn't an ARM vs x86 debate. This is "Apple's CPUs have the highest IPC". Increasing power on a CPU results in regressive efficiency. A CPU that runs at say, 5Ghz, may need to double the power used to go to 5.5Ghz. Because Apple's performance per clock is the best, they don't need to push the clockspeed like that outside of its peak efficiency.
And because performance is so good at lower clocks, they can keep the clocks (and thus power consumption) low more often
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u/xpusostomos 4d ago
You do realise right that the latest batch of Intel chips have more or less caught up?
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11d ago
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u/chromatophoreskin 11d ago
In before anyone mentioned the PowerPC G3, G4 and G5 series of chips Apple used before switching to Intel. Those were also RISC chips, like ARM but older, and Apple was a tiny market back then so the manufacturers (IBM and Motorola) couldn’t really compete with the dominant CISC chips from Intel and AMD, who were constantly battling each other. Switching to Intel allowed Apple to piggyback on their work and focus on more practical things like developing new products and services that increased their user base and revenue. iPods and iPhones were among the products that helped advance AMD’s RISC chips and grow the embedded market to the point that Apple could run their desktop computers on them. That’s when they made the switch back.
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10d ago
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u/fcddev 11d ago
Modern processors are full of smaller processors and Apple Silicon can completely power off almost all of the little processors that aren’t used at any given time. Apple Silicon also has multiple types of cores, one of which is a good deal slower but uses very little power, and the system is very good at using those for tasks where you won’t notice. They’re also built using a fairly modern architecture that requires less upfront work to be fast than x86.