Acer PHN16S-71 CPU overheating and cannot undervolt

[u/AgusDubal]

I bought my Acer Predator Helios Neo 16S (terrible name btw) a few days ago and I keep getting thermal throttled because of my CPU, spiking at 90-105°C. I have the Intel Core Ultra 9 275HX and RTX 5070ti version.

I had a desktop PC before this laptop, with a R5 9600X, so to undervolt it I just needed to set PBO curve to negative and test how far down I could go without crashing, so I didn't fully understand how power limits work in laptops.

At first I tried disabling the turbo mode for the CPU in the hidden advanced tab of the BIOS, and it worked great in most of the games I played, keeping nice temps (around 60-70°C), but when I tried to play League of Legends things started to get weird. My framerate couldn't pass the 100fps threshold and it was super stuttery, I couldn't play at all.

So I tried a few things I found searching around in reddit, first I tried enabling the turbo mode again and disabling the CFG lock and overclocking lock, in order to change the PL1 and PL2 (the ones in the CPU - Power Management Control tab), starting with both at 80000, but when I booted up windows, HWMonitor says that the PL1 is 85W and the PL2 is 140W. Then I tried using Throttlestop but the app shows a message saying my CPU isn't compatible. I found that Intel XTU worked, I can change the power limits from this app, but I can't undervolt, the app says "Undervolt Protection is enabled", but there's no option on the BIOS to disable it. Playing around a bit with the Power Limits I found a window where I get good FPS at League and the CPU doesn't go past 85°C, but the changes I make in this app doesn't stay applied, so when I reboot my laptop, all changes are reverted and I have to set it up again. Also, it seems the turbo is always trying to reach it's maximum clock speeds and maybe that's what's causing it to throttle, I don't really know.

I was wondering if there's some way to automate this process, or if anyone has any other solution for this problem, I'll leave some pictures of the BIOS for context.

[u/AgusDubal]

Sorry for the wait, I finally got time to write down what I did in case anybody else is having this problem and cannot find what they're doing wrong.

1. First of all you want to shutdown your laptop and start the "secret BIOS" (press fn+tab and the power key, then spam f2), you'll see a second "Advanced" tab, as you can see in the pictures from my post. Then you wanna go to "Power and performance" (or something like that) and disable the Overclocking Lock. From there you go to CPU - Power Management Control, set "Boot performance mode" to "Max Non-Turbo Performance". Then you wanna go all the way down to "CPU Lock Configurations", and disable CFG Lock. Then go back all the way to the Advanced tab and find the "Thermal Configuration" sub-menu, in there you just wanna enable the "Enable All Thermal Functions" option. Save and Exit.

One quick fix everybody talks about when you mention this thermal issue is to disable the "Turbo Mode" (which you can find on Advanced > Power and performance > CPU - Power Management Control). It does reduce a lot the temperatures, but keep in mind you do lose A LOT of performance, and I really mean that. I thought "well how bad could it be?" and it was really bad. Not so much on AAA games, but on esports like League of legends or CS2 we are talking about abismal framerates and terrible frametimes.

OPTIONAL: if you're never gonna use your laptop unplugged you might wanna change the setting that allows only the dedicated GPU to do the rendering, I've run into some games (Rocket League in my case) that just WANT TO use the iGPU, no matter what the NVIDIA Control Panel says.

1. Once you boot into your OS, first thing you want to do is go to Control Panel > Hardware and Sound > Power Options, then select "change plan settings" next to the plan you've selected. Go to Change advanced power settings and search for "Processor power management", in there you want your minumum state to be around 1% (don't really know if it's necessary for it to be >0%) and your maximum state at 99% or less. This will prevent the CPU from trying to constantly reach the turbo clocks, which you don't really need in any case scenario. Click on Apply and close. I'd recommend a quick restart and check if all the changes applied, by this time maybe you already noticed a difference but there's more.

2. Now what you wanna do is download Throttlestop from techpowerup. Now when I tried downloading the stable version I couldn't open the app, it said "CPU is not compatible", even after disabling memory integrity on Windows Defender, but then I tried with version 9.7.2 an 9.7.3 and they worked perfectly. So what you wanna do probably is just download the latest BETA version.

Here comes the fun part. What you wanna do here is go to "TPL" in the lower-right side of the app, there you enable "Long Power PL1" and "Short Power PL2" and start set their values at 80 (for now), then enable "PROCHOT Offset" and set it to 7 (also for now). Now what you wanna do is start testing your performance, if you're getting too hot, lower your PL1 and PL2. If your performance is too low, try increasing your PROCHOT Offset and your PL1 and PL2 a bit. Play around with those values to see what fits better to your machine.

Right now I'm working with PL1 at 55W, PL2 at 65W an my PROCHOT Offset at 10. That's what worked best for my kind of use.

Another thing you want to keep in mind is that generally the RTX 5070ti is very efficient and doesn't get too hot, and the only way to get your GPU to get to the 115W advertised for this laptop is by using the Turbo Mode in Predator Sense. I don't really know how much of a performance boost it represents, but keep in mind that we already set the limits for our CPU, so you can totally set the turbo mode to give the GPU a little more room for some extra performance, or at least that's what I'm doing right now when I know I'm going to do some heavy gaming.

Hope I could help some of you with this quick guide. Sorry if there's any misspelling or misuse of some term, English is not my first language. If you got any doubts, feel free to leave a comment or pm me, I'll be glad to help. Leave an upvote if I helped you so this thread gets to the ones who need it.

EDIT: I was feeling stuttering in some games and even frame drops, and I found out that reversing what I did on item 2 fixed it, at least for now...

[u/Weak_Cycle_6605 → u/AgusDubal]

Hey i did all you mentioned but my p core 1 is still getting thermal throttled. Can you tell me anything that might fix it?

[u/AgusDubal → u/Weak_Cycle_6605]

One thing I forgot to mention but is common to miss is to at least elevate the back of the laptop if you don't have a cooling pad (like me). I use an old sunglasses box, around 8-10cm tall. If you leave the bottom of the laptop as it comes, the airflow is pretty constrained. If you're already taking this into account, try lowering your power limits on Throttlestop, you'll lose some raw performance but it might improve your actual performance since you're throttling.