Strange CPU power throttling behavior on 2022 Helios 300 PH315-55-7174

Been trying to figure this out for a couple days, including making this post on the ThrottleStop forum, but no luck.

Long story short, this is a 2022 Acer Helios 300 PH315-55-7174 with an i7-12700H and an RTX 3060. From a fresh boot, the CPU will boost all the way up to 110W in a CPU-only workload and mostly stay there, which is great.

In a combined CPU+dGPU workload (like a game), the CPU will throttle down to 45W, which is probably normal because there seems to be a combined 150W limit for CPU+dGPU from what I've observed, and since the dGPU typically maxes out at 100W in games (120W in FurMark)… the math checks out. I have to say it's still a bit disappointing considering the specs say it's a 140W 3060, which obviously isn't gonna happen in practice with an apparent 150W combined limit unless the CPU is completely starved and the limit also seems kinda low for a 280W power brick, but eh, whatever, I'm happy enough with the gaming performance so I can let it slide.

The problem comes when the GPU usage stops. At this point, the CPU's power limit is raised to 56W, which itself is weird, but the real issue is that it will simply stay there. No matter how long the GPU remains idle, the CPU is never able to boost back up to 110W, even after hours. The only way to get that performance back is by rebooting, and not engaging the dGPU in any significant way.

You can check the linked post above to the TS forums for some screenshots and logs showing the behavior.

By this point it looks likely that it's some kind of flaw in how the power limits have been implemented at the embedded controller level, and there's nothing software like ThrottleStop can do to change this. But I wanted to make this post just in case anyone else has noticed this behavior on this laptop or similar models, or if anyone has any ideas regarding what could be done to address this. As far as I know, my laptop has the latest BIOS updates as well as the drivers directly from Acer's website, but I don't know if any of that would have an effect on this behavior.

[Edited the thread to add model name]

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PositronCannon

I forgot to mention this, but to be clear, temperatures are not an issue at any point through these tests. The throttling is entirely power-related, artificial, and seems arbitrary and unnecessary in the case of this 56W limit that won't go away.

edit: oops, sorry about the double post, I couldn't find the edit function for the initial post at first.

JackE

Is it plugged in and battery charge level near 100% when it won't go above 56watts?

PositronCannon

https://community.acer.com/en/discussion/comment/1197941#Comment_1197941

Yes to both.

edit: also, I've been experimenting with the higher performance modes on PredatorSense since I made the post, and both the Extreme and Turbo modes seem to increase the dGPU and overall power limits, as I've seen 140W from the GPU and 170-180W from CPU+GPU on those modes. However, it has no effect on the CPU and this 56W limit remains in place regardless, until I reboot.

JackE

Without undocumented BIOS mods, Predator Sense would likely be the only way to affect this. Do you have the latest Jan 6 version installed?

PositronCannon

Yeah, I got this laptop a couple of weeks ago and I downloaded the application directly from that page, along with all the drivers.

PositronCannon

Okay, so I just made it worse. I figured I'd try making sure I was on the latest BIOS version just in case. Turns out I was on 1.05, so it updated to the latest 1.10 BIOS.

Now even immediately after a reboot, the CPU will trip PL2 right away maxing it out at 56W, and even worse yet, PL1 will engage after less than a minute, capping it at 45W even with no dGPU load whatsoever.

So my CPU is now basically running at well under half its power for no reason whatsoever, considering it's only reaching 65C and the power delivery is well capable of feeding it 100+W as shown before… well, that's just great. :|

JackE

Did you shutdown, unplug the charger and then press & hold the power button for about 10 seconds for a reset? Then check it again?

PositronCannon

https://community.acer.com/en/discussion/comment/1197969#Comment_1197969

Yep, still the same behavior.

I even went and downgraded the BIOS to 1.03, the oldest provided on Acer's site, as a last resort to see if maybe that version behaved differently or at least allowed for modification of the power limits to something less absurdly conservative, but no luck. It seems that whether the CPU is allowed to boost to its maximum 115W or not is effectively random after a reboot, and it wasn't caused by the latest BIOS update after all. I can only guess there's some sort of flag that gets tripped and locks the CPU into its PL2 limit from that point on, but I have no idea what it is (aside from high dGPU usage which consistently triggers this state).

At this point I'm completely out of ideas. Unless anyone has anything, I'm just gonna assume that the CPU on this laptop is way underutilized by design, and it may actually be an oversight that sometimes it is allowed to run at its full power.

JackE

I'm just gonna assume that the CPU on this laptop is way underutilized
by design, and it may actually be an oversight that sometimes it is
allowed to run at its full power.

Yes. v1.05 might have actually been the oversight. Because I think it's a laptop heat management issue. And 1.05 might've gone too far with allowing too much power for the thermal modules to adequately handle heat dissipation. Sometimes causing premature processor failures.

PositronCannon

Old topic, but I wanted to post an update in case anyone with the same issue stumbles across this topic.

As it turns out, updating to the latest BIOS 1.11 (https://www.acer.com/us-en/support/product-support/PH315-55/downloads) seems to have corrected this and the CPU is once again able to boost up to 110W.

Even better, I haven't seen the old behavior of PL2 getting stuck after a GPU-heavy application was active, though more testing is needed on that front.

Given previous experiences, it's possible it's still random whether it can boost to that point or not, but considering I literally never saw the CPU go above 56W after updating to the 1.10 BIOS, and now it's boosted to 110W every time after 4 reboots… it's pretty promising.