# Throttlestop cpu throttling under load i7-9750H



## TheLievre (Nov 14, 2020)

I recently bought a brand new "Acer Predator Triton 500 rtx 2060" laptop and I'm running into throttling issues when the cpu is under load.
About 1 second into Cinebench R20 benchmark my PL2 limit triggers, along with RING EDP OTHER, shortly after CORE EDP Other and GPU EDP OTHER.
Then about 8 -10 seconds into the benchmark my PL1 limit triggers and by this point my cpu is throttled down to ~3000mHz, from ~3993mHz.

I also some very odd THERMAL throttling when using TS BENCH. Before starting the benchmark my cpu temp is hovering around ~50C and then immediately(~1 sec)  when I start the bench it reaches the PROCHOT temp at 95C, alongside the PL2 and RING EDP OTHER. The odd thing is that immediately when I stop the TS BENCH, the cpu temp drops right back to ~55C. Is that normal?

I read online that my cpu is limitted to 45w, which is why I left my long power max at 45.

I'm still a little bit concerned with all of the yellow and red limits being reached when under load. I'm hoping that someone has a good understanding of if any of this is normal. If not, do you think there is something defective with the build and I should send it back for testing/repairs or is there something I can do to fix the throttling on my end.

My current BIOS version is 1.11. Would updating the bios help in any way?  I haven't pushed my core/cache undervolt past -125mV, would it be a good idea to try that out?

Thanks a bunch, I really appreciate the help!


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## rethcirE (Nov 14, 2020)

Nothing defective on initial read. Acer is known to set conservative defaults even on their top-tier gaming systems.

The 9750H has a 45W TDP but you can push it higher. The PL1/PL2 limits are directly tied to the stock values (45/60W probably). If you unclamp and up these numbers, the limits will be higher as long as the BIOS/firmware allow it.

Start here - https://www.ultrabookreview.com/31385-the-throttlestop-guide/
Reference - http://forum.notebookreview.com/threads/the-throttlestop-guide.531329/

If you search the reference thread for "9750H" you can find other users settings and compare.


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## TheLievre (Nov 14, 2020)

Ok great to hear, thanks! I will bump up my limits a little and see if the BIOS/firmware allows it


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## unclewebb (Nov 14, 2020)

@TheLievre - Your log file shows that after only a few seconds, the short term power limit (PL2) is enforced at 45W. A 9750H cannot achieve maximum performance at this power level. Power limit throttling will be the result.

You already have the FIVR - Disable and Lock Turbo Power Limits box checked so it does not look good. Acer has limited your beastly looking laptop to the 45W TDP. Too bad manufacturers do not have the spine to admit this before you buy a laptop from them.

For comparison, the exact same CPU in a laptop with good cooling and unlocked power limits can score over 3000 in Cinebench R20.

Try increasing only the CPU core offset. Go up in steps of -25 mV. Most people achieve their best Cinebench scores with the core somewhere around -200 mV to -220 mV. If you lose stability while testing, reduce the cache from -125 mV to -100 mV. It is usually the cache offset that causes problems. This will not solve all of your problems but it might help you get a little more performance while having to operate within the 45W TDP limit.

If you are using any Acer software, make sure that it is set to performance and not cool and quiet. Some software from manufacturers can lower the turbo power limits.


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## TheLievre (Nov 14, 2020)

@unclewebb Well that's really unfortunate... Ok great I'll try that out to see if I can squeeze some more performance out of it. I'll let you know how it goes.

Thanks, I really appreciate your help!


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## unclewebb (Nov 14, 2020)

TheLievre said:


> to confirm that they actually limited it to 45W TDP


This is easy. Run Cinebench R20, about 5 seconds after the CPU reaches full load, your laptop is either going to start thermal throttling or power limit throttling. Watch the CORE column in Limit Reasons while Cinebench is running. PL2 is going to light up in red and the main screen of ThrottleStop is going to show power consumption right at 45W. I am assuming that during any strenuous test, both power limits are being locked to the same 45W value.

This is done internally and it is done deliberately. There is no easy way around this limitation.

You bought a laptop with a CPU that has a 45W TDP rating so if you complain to Acer, they will likely tell you that your laptop is running as designed. If you just bought this laptop, consider returning it. There are laptops from other manufacturers that are not as limited. Before buying anything, you need to do a lot of internet research. Comparing the CPU model number has become pointless. Depending on how the power limits are set, two laptops with the exact same CPU can perform vastly different.

A BIOS update could make things worse. Starting last December, many BIOS updates are disabling CPU voltage control. These updates are also disabling turbo ratio limit control. I would not update anything unless I could confirm that the new BIOS still allows voltage control. Without voltage control, your temperatures will be higher and you will hit power limit throttling sooner so your CPU will run slower. Try to find an Acer specific forum (Notebook Review) so you can see what sort of problems other users are having with this exact laptop model. Many review sites completely ignore laptop throttling issues so you have to speak with people that own these laptops.


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## TheLievre (Nov 14, 2020)

@unclewebb - I just bumped up my Long Power Max to 60 and my Short Power Max to 80. I undervolted the CPU core in increments of 25 mV all the way to -250 mV and everything seems stable so far. I ran Cinebench every step of the way and got my best score of 2720 at -220 mV. At -250 mV my Cinebench score was slightly lower, at 2697, but I think the difference score is negligible.  Is it a good idea to keep undervolting past -250 mV until I see a loss of stability or crashing, or do you recommend leaving it at -250 mV.

I was considering returning the laptop but I got it a steal of a price during Amazon Prime Day. From 2,199$ CAD to 1,424$. Then just this week I got an email from Amazon saying that they were able to offer me a better deal and refunded me 309$. Bring the total cost down to 1,115$ + tax. Even considering the throttling I don't think I would be able to find myself a better laptop for the same price.


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## unclewebb (Nov 14, 2020)

Most of these CPUs reach peak performance at approximately-225 mV. The CPU ignores viltage requests beyond this point. 

In the log it looks like when thermal throttling starts, that triggers your computer to go into low power mode. If you replace the thermal paste or find a way to improve cooling, it might help avoid these power drops.

Your laptop is running much better. Look into blocking BIOS updates. Losing voltage control would sacrifice a lot of performance.

Sounds like you got a good deal. It may not be perfect but it is far from horrible. During games it will not need 45W so it should run great.


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## TheLievre (Nov 14, 2020)

@unclewebb - Ok sounds good I'll drop it back to -225 mV.

Yeah with the extra performance you helped me squeeze out of the system I'm quite happy with it now. 

Thanks again for all of your help!


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