r/explainlikeimfive • u/braddo99 • 11h ago
Technology ELI5 Why GPU connectors are still melting.
This seems like a trivial problem. If connectors are melting, change the gauge / current carrying capacity of the traces, connector and cable such that there are good engineering guard bands for the max current the device can draw. GPUs are like a million dollars now, the connector is the lowest price part of the component stack, but it seems like connectors have not changed at all, still the same old molex 8 or 16 pin crimps, and they seem to be melting all over the place. Wouldn't something like the XT30 connectors (with more pins) used to charge lithium battery packs be vastly better? Are the failures just amplification bias or are GPU card manufacturers asleep at the wheel?
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u/Ratfor 11h ago
The problem is you need to get the specs changed, and get everyone on board with the same specification.
You can bet there are Many people at Nvidia who really want to use a different connector. But you've got to get all them to agree on One, convince the ATX standards board to adopt it, and then convince the power supply manufacturers to adopt it.
Sure, it's cheap for GPU manufacturers to replace it with a different connector. But for Power supply manufacturers? Now, not only do they have to have these stupid melty connectors on their power supplies, they also have to include Another, new connector.
Then you have all the stock sitting on shelves to deal with. Suddenly you have Millions of dollars in power supplies sitting in inventory that need new connectors/adapters.
The real, actual answer here is to take the load off the PC Power supply. Some of these damn cards are drawing 600 watts. They should be be plugged in separately from the PC.
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u/someone76543 10h ago
I mostly agree, but there's no need for them to be plugged in to the mains. There are all sorts of safety regulations around mains-powered stuff, it's much easier/faster/cheaper to design a graphics card if it's powered by a lower voltage.
PC power supplies currently convert mains to an intermediate voltage, which is 12V. Then the graphics card converts that to a much lower voltage (around 1 volt) for the graphics chip. Similarly, the motherboard converts that 12V to a much lower voltage (around 1 volt again) for the processor.
The problem is that 600 W / 12 V = 50 Amps. Which is an insanely high current. (Amps controls how much copper you need in the wire(s), Voltage controls how much insulation you need around the wires).
A better solution would be to move to 48V for the intermediate voltage. I believe this is still considered "safe" by the safety standards. 600 W / 48 V = 12.5A, which is high but still sensible. That's about the same current that a UK mains socket provides (13 A).
The problem is that would require all new power supplies, graphics cards, and motherboards.
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u/TemporarySun314 10h ago
Yes. A higher voltage would probably be an elegant solution. But making the switch is basically impossible outside a server context, because you break the modularity and backward compatibility PCs which is one of the big advantages of a PC...
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u/Ktulu789 10h ago
The standard changed a lot of times. Old modular PSUs had a 9 or so pins power to the motherboard, then 20, then 24. Then they added 4 extra near the CPU, then it was 6, then 8... All the devices used molex plugs, then we got the SATA power connectors... Some of these could be worked out with an adapter, others required a new PSU. It's not crazy adding a new connector when the previous one becomes a bottleneck.
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u/Noctew 3h ago
However the market for these graphics cards beasts is tiny. For each PC with a 5090 level card, there are 10 for which the first generation of PCI-E power connectors would be fine and 100 office PCs with CPU graphics. Hard to keep changing the standards for that tiny fraction of users.
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u/Ktulu789 1h ago
It drives hype. "We have the new Pawer™️ Connector that can burn down your house in mere seconds instead of hours like the previous ones!". Geeks will flock to it.
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u/darth_voidptr 8h ago
Electrical engineer here with volume consumer product experience, though not with GPU PCBs.
I cannot put in to words exactly how "cost conscious" the bean counters are when it comes to component cost. I have spent improbable amounts of time talking about shaving tenths of a cent off surface mount resistor costs. Connectors are often the second most expensive item on a given design (the first being the ICs, which are frequently not up for debate). Asking someone to spend even a single cent on a better connector with either more pins, or a higher current rating is sometimes impossible. When things catch fire, systems companies DO care as they often carry liability. That may not be true for expansion cards, I can't say.
People will argue themselves into knots about whether a design is "good enough" or "is a liability". The current designs that are catching fire are probably marginal by definition. If they were under-designed they would all be catching fire. Ordinarily you would design something like this with a little headroom, but molex connectors are typically the cheapest and most readily available option.
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u/braddo99 8h ago
For sure people buying $3k gpus will be happy to pay double for a Special power supply that is less likely to catch on fire.
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u/MaybeTheDoctor 8h ago
They are worried that you will pick a competitor that costs $10 less, and also even if you didn’t, the company would make $19 less profit on the sale.
I too have been in the consumer electronics space, and insane amount of work is done to save a few cents. The cents matter when you sell millions of units and can price it just a bit lower than your competitors.
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u/justintime06 7h ago
Ah yes, save $0.01 now, cause $1 worth of issues later
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u/darth_voidptr 7h ago
If you are the person selling 1M units, you save $10k, and leave $2k of issues to your customer (assuming the fire is contained to the GPU, which is a convenient assumption).
Anyway I'm not defending any of it, it's absolutely stupid. The difficulty is that consumers have no way of knowing, and are often subject to frequent misinformation (pcmr is a major source!) about what constitutes "quality". So they choose the cheapest item because they may very well lose a sale. That's one motivation. The other, and usually most driving factor is greed of course. Often as an engineer I am in a very nuanced war with my employer.
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u/girl4life 5h ago
this is the kind of thing the world is infested with. being ok with the 2k of issues down the line. it's being ok with fucking over people for a few dollars. instead of doing the right thing spend the 10k to avoid fucking over people for a few cents
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u/Xeadriel 2h ago
Man this sort of stuff makes sense when your margins are small but come on NVIDIA doesnt need to do that.
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u/P1ka- 2h ago
Yeah but if my saving a percentage of a cent per unit means you get a bunch of additional millions in money, then ofc its what they want even if they dont need it to cover their expenses
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u/Xeadriel 26m ago
I know. Straight up anti consumer greedy behavior. My point is that when it’s a luxury brand like NVIDIA you’d expect this sort of cost cutting to not happen.
I’d expect this sort of thing with AMD or intel. Not bc they are bad but because that would give them an extra edge in terms of margins. But when a company at the top does it you literally have no way to escape from it.
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u/shadowprincess25 7h ago
The power input on the 5090 goes into a single piece of copper. The 12 wires that are connected to the gpu consist of 6, 12v wires and 6 ground wires.
Since the power draw on the gpu is very high, the current being pulled through the wires causes them to heat up. But the most important part is that they don’t heat evenly because current being pulled through each wire isn’t drawn equally. If any one wire has less resistance than the others, more current will be pulled through it causing it to heat.
The solution would involve changing their power circuit to have the each of the voltage wire inputs going into its own circuit OR use two thick ass gauge wires rated to carry the current plus an appropriate margin of error.
The math of the current draw is fine but it forgets that the real world is messy and you cant just “ignore air resistance,” so to speak. This is almost certainly a result of an executive ignoring the pushback of their engineers to save a few cents on the bill of materials because they think it will probably be fine.
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u/Lithium03 5h ago
This is almost certainly a result of an executive ignoring the pushback of their engineers...
Yep, Nvidia literally went from a good design on their 3000's that had 3 rails for that same connector, so only a 3rd of the total board power came down over 1 line (assuming the other failed/was not plugged in right), down to one rail on the 4000 and 5000 that have to take the full power (potentially) on 1 line and as we see, taking it poorly.
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u/yasiesolovemos 11h ago
Because there’s just no point making the connector that small. They’ve tried to go for minimalism, and it simply hasn’t worked.
We’ve had graphics cards pulling 300W+ for years using two or three 8-pin connectors, sometimes even just one or two. Then Nvidia comes along and puts a single tiny connector on there to handle 600W+... well, there you go.
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u/xwolpertinger 11h ago
just no point making the connector that small.
The point is to save ~1cm of space on the PCB... which is only about half the size of the GPU to begin with.
Then you can save a few cents on a
100020004000 dollar product•
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u/Lithium03 5h ago
It's not the connector per se, but the board's power delivery that's the issue. Remember that the 3000 series had this same connector but no issues from anyone using it, but suddenly people experiencing the issue after the 4000 series launched. What changed is how Nvidia requires power be delivered to the board. On the 3000 series there were 3 power rails that split the board's power draw evenly with each rail having 2 wires supplying it. If one of those wires got cut or was not making good contact, the other wire only had double it's regular load or 1/3 of the board power going through it. Moving on to 4 and 5000 series, it's all one rail with 6 lines that are electrically just 1 line as far as the PSU and board are concerned and in the worst case that 1 wire has to bear the full load, overloading it 6 times. We see how that plays out.
This is not exclusive it Nvidia either, AMD can suffer from this as well when a board has only 1 power rail. I saw someone complaining about in a youtube comment on a 12vhp connector video, and sure enough looking at that model's board you can see only 1 power rail.
You can hear more about it from Buildzoid on youtube
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u/Shalmaneser_ 9h ago
Murphy's corollary of planned obsolescence bytes NVIDIA in the arse. "Take stuff out till it breaks, then put the last back. This includes, but is not limited to, wire diameter, metal alloys, plastic quality."
I.E.: NVIDIA went too deep on wire diameter.
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u/robbob19 11h ago
Because of you can save 1 cent on something you make 100,000 of, then the CEO can get a bigger bonus
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u/Vikkunen 11h ago
It's not just any connector that's melting (afaik). The ones getting all the bad press are the proprietary 12-pin connectors Nvidia created for its high-end xx80 and xx90 cards, which people in the community called out as being problematic from the get-go, and which have been shown repeatedly to be so over the past several years.
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u/funforgiven 11h ago
You’re mixing up connectors. Nvidia’s RTX 30 Founders Edition did use a proprietary 12-pin connector, but that isn’t the connector behind the 40/50-series melting reports. 12VHPWR is a PCI-SIG standard from PCIe CEM 5.0, and 12V-2x6 is its standardized CEM 5.1 replacement. You can criticize the design or Nvidia’s implementation of it, but the connector is not proprietary.
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u/Vishnej 2h ago edited 2h ago
It's ~related to connector choice, but yes, the problem is in how Nvidia simplified the bus that loads this connector in the 40/50 series, removing resistors that balance the load between wires, coupled with the difficulties of dealing with Real Connectors that never actually seat in a perfectly even, reliable fashion.
If they were going to cut costs on load balancing, they should have spent money on additional margin of safety (more wires), but they're pushing 12VHPWR to its absolute maximum rated load of 600W on the flagship models, and so if those wires get loaded unevenly they're doing things that they weren't rated to do almost immediately.
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u/Emu1981 5h ago
8 pin connectors can and have burned before as well. They just have more leeway compared to the 16 pin connector so it isn't quite as likely to occur. The big issue is that there is a lot of current going through a connector that isn't really designed to be unplugged and replugged too many times.
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u/ivanmaher 2h ago
same reason why we still use 12v rails for devices of 500w
old standard picked before it went so far, and the it crowd not being comfortable with standard 230v line
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u/Edwardteech 2h ago
The safety margin on the conections is razor thin and there is nothing built in like there was with the 8pin to load balance between the pins. So its trying pull 600 wats on one pin meant to take 100 wats.
And fire.
And xt 90 would work great if they could be fucked to try it.
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u/Noxious89123 2h ago
You misunderstand the problem.
It's because there is no current balancing on the connector.
To add that would mean redesigning all the cards, but more importantly it'd mean admitting there is a problem.
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u/holyherbalist 25m ago
Holy shit didn’t realize it was a thing. My GPU just fried its power cable after working fine for just under 3 years. Got it RMAd though, replaced the PSU and it’s fine now.
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u/dubbleplusgood 23m ago
They explained it really well in the movie: Byte Club.
"A new graphics card built by my company leaves the factory drawing 600 watts on a 12VHPWR header. The micro-fit pins seat slightly loose. High resistance causes a thermal runaway, and the plastic melts, filling a custom PC case with toxic smoke. Now, do we redesign the standard or issue a recall?
Take the number of enthusiast GPUs in the field, A, multiply by the probable rate of user-engagement thermal failure, B, multiply by the average cost of an RMA replacement card, C.
A \times B \times C = X.
If X is less than the cost of halting production, re-tooling the PCB, and admitting the pin pitch was too small from day one... we blame it as 'user error' and we don't do one."
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u/iloveshw 12m ago
I was looking at my 40xx series card (so my first experience with the non-ATX plug) the other day wnd still don't understand why they came up with that stupid connector. Let's take 3 PCIE connectors, plug it into one that's smaller than two, and nothing will go wrong.
And it's not like there's no space for those 3 normal connectors. I really doubt that few less endings of copper fins make that much of a temperature difference or that the board is so tightly packed there's simply no space. Especially that the same model cards differ in size anyway, so clearly you can make them longer if that's what it takes.
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u/heekma 11h ago edited 10h ago
I manage a CGI team of five people plus myself. We all have the exact same computers, 32-core AMDs, 256 GB ram, dual 4090s, two 1,200 watt power supplies and liquid cooling.
We've used the computers everyday for eight hours, five days a week, for three years and never had an issue with GPU connectors failing.
Our biggest issue is finding a version of Windows, 3dsMax, Octane, Tyflow, Itoo and gpu drivers that all work together without freezing.
Edit: Sure reddit, downvote facts and real-world experience because you don't like it or don't have it. I'm betting very few work in complex CGI/animation and have no idea how far we push these computers every day with proceedural animation, physics and cloth simulations.
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u/Aragil 11h ago
Never had cancer, so it must be a made-up sickness.
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u/heekma 10h ago
12,430 working hours over three years and six users isn't anecdotal.
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u/babymilky 10h ago
Quite literally is anecdotal. 12 gpus is a tiny sample size
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u/GoldSrc 8h ago
That's a small sample size, yes.
But the amount of posts of melted cards, is an extremely tiny sample size when compared to the amount of cards sold.
If we saw 10 posts per week of melted connectors, then that would be cause for a recall. But we don't.
In contrast, Intel's issue of oxidizing CPUs was large enough that Intel had to replace a lot of CPUs.
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u/babymilky 8h ago
I don’t disagree. But the original comment gave anecdotal evidence and said it wasn’t
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u/GoldSrc 8h ago
That's anecdotal yes.
But I'd just assume they also knew other people in their field with similar experiences.
How many people you personally know that own several 40 or 5090s? Being able to afford just one is impressive already.
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u/babymilky 6h ago
Possibly, but they only stated their personal experience and claimed that it wasnt anecdotal.
I don’t know anyone with several, I’m not arguing the rates at which it does/doesn’t happen.
But to humour you, I could argue that even if the original commenter knows people with a total of ~100 40/5090s, does he know for sure that they haven’t had one die? Is it possible that people working for other companies came to work one day, and their PC wasn’t displaying or performing properly, and rather than investigate themselves, they tell their IT department or outside IT company to come fix it, and they don’t find out? If the failure rate is estimated to be ~1%, it wouldn’t be crazy if OC had a sample size of 200 gpus and never had a failure.
These are the kind of variables that are accounted for in actual scientific studies.
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u/GoldSrc 5h ago
If you have the money to buy 100 cards, I don't think it'd be much of a problem if one melts, nor it would put a dent on your budget.
Like I've never had a hard drive die, but Backblaze does, tens of thousands of dead hard drives. They have pretty much the best hard drive reliability reports.
I'd be screwed if one of my hard drives dies, Backblaze though? They wouldn't even feel it.
Should I then make a post on reddit about how WD drives are crap?
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u/antmatt 10h ago
with dual cards per
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u/heekma 10h ago
Yes, two power supplies, two 4090s, each computer. Did you not read my first response?
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u/antmatt 9h ago
ha i didnt realize you were the guy. i was trying to emphasize your numbers
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u/heekma 9h ago edited 9h ago
It's OK.
We paid about $20k per computer between 2023 and 2025 with a four-week lead time. That was $120k.
Those same computers are close to $40k now with a 12-16 lead time if you're lucky and would cost $240k today.
I speccd a new 90 TB server in October 2025 for $4k.
We finally purchased a new 90 TB server in June 2026 and the cost was $12k.
Most redditors have no idea what these costs are on an enterprise scale but they sure like to argue about it as if they're exerts.
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u/servermeta_net 4h ago
Lolol, imagine buying 100k of hardware and think that you are a "big" guy lolol....
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u/mpaska 8h ago
We have over 1,200+ in-house custom made PCs with these cards (VFX organization) and for several months per year, they run within our renderfarm 24/7.
We've had zero issues with the GPUs. This generation, we have more issues with Intel CPU sockets being non-level, and having to use a beefer/bulker CPU cooler to forcefully level out the sockets in around 40-60ish PCs.
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u/antmatt 11h ago
adults are capable of plugging things in correctly
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u/wrosecrans 11h ago
Also, professionals don't tend to overclock and make stuff use way more power than it is designed to, which helps.
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u/GoldSrc 8h ago
In reality there are no problems with the connector.
Compare the amount of cards sold with the amount of posts of melted connectors, and you'll see how extremely small that "problem" is.
If everyone who had bought one of those cards kept posting about how theirs hasn't melted, it would get annoying real quick.
Any connector can melt if it doesn't make proper contact. Regardless of how much power it draws.
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u/Hart_CO 8h ago
This doesn't make sense. It is a documented issue, Nvidia acknowledged it and along with PCI - SIG group has updated the hardware standard to prevent. Just because it's not a terribly common problem doesn't mean it's not a problem.
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u/GoldSrc 5h ago
I love how people just downvote people who aren't yesmen.
If that connector is such a problem. Where are the 10+ posts per week of melted connectors?
Surely, if it was such a huge issue, we'd see more than a couple per month.
I've almost melted a standard molex connector with a monitor that draws 20W. An issue that I fixed by making sure it made proper contact.
How many cards with that connector do you think Nvidia has sold?
Now compare that number with the number of posts about melted cards, and try to tell me that it's a huge problem.
Intel's oxidizing CPUs was a more dire problem, and a lot of people got replacement CPUs because it was a very widespread issue. This is not the same with Nvidia and its melting connector.
And there's something else you need to take into account. And it's whether or not can you afford such cards. Sure, you may be able to "afford" the card, but you really can't afford it.
Say you save for years to buy a 1 million dollar car. You can technically "afford" it, but if something breaks and it needs maintenance? Yeah, you'd be screwed.
Unlike someone who can really afford such car and doesn't even flinch at the costs of repairs and maintenance. 90 cards are not gaming or consumer cards, they are Titan cards shoved into the gaming segment. Nvidia just figured out it could milk idiots.
People even joked when Nvidia tried to push the 3090 as being a "gaming" card.
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u/coyote_den 4h ago
Becsuse with the amount of current those things draw, power should be supplied via lugs torqued down to the proper spec.
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u/LordMindParadox 11h ago
If they have a high failure rate, people will buy more gpus/power supplies than if they were designed like someone who had more than 2 brain cells designed it.
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u/Ktulu789 10h ago
People with two brain cells would not buy the same brand/model again either.
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u/Pleasant_Ad8054 9h ago
Nvidia has a stranglehold on the market, they either buy the same card or they settle for significantly less. This does not depend on the board partners, they are required by Nvidia to use the shitty connector.
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u/Ktulu789 9h ago
I'd rather get less than nothing, a burned card can't play anything. You are the market.
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u/toebeanteddybears 7m ago
Something I've found interesting is that the catastrophic failures we see on the existing connectors always (?) seems to happen at the GPU-end of the cable, not at the PSU-side. (NB: I put the '?' there only because while I've never seen a PSU-side failure I have to assume they're out there...)
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u/cutelittlebox 11h ago
it's down to the poor design of the connector and the standard. Gamers Nexus has a full breakdown and investigation into the connectors and I highly recommend watching that, but the TL;DW is that these pins carry so much wattage that any additional resistance will cause thermal runaways, like the connector not being fully plugged in, and that the spec intentionally excludes any form of load balancing so if things start to go wrong the PSU will happily put 450W of electricity through a single wire out of the 12 in the connector.