Intel 8750H Unlock for Undervolting and XTU or Throttlestop Use.

[Errolw98]

Hello All,
I have a Dell XPS 9570 with the intel 8750H and have been doing some research and searching for a solution to decreasing internal heat buildup in the field.
The laptop in question is used many times in higher ambient and humidity conditions (80-90 Deg F. at 65-85% Hum) with possible sunlight exposure although I try to minimize this. While I have not documented this, I know I have experienced mild to extreme throttling in some instances. To minimize this in the future I am replacing the Thermal Paste with Thermal Grizzly Kryonaut and adding Thermalright pads on MOSFETS that should just contact the bottom case cover along with a through cleaning of the fan grills and air paths to ensure the best thermal conductivity from the chassis.
In addition I would like to experiment with Either Intel XTU or Throttlestop performing some undervolting and load testing for best bench results. I fully understand that Undervolting may or may not help in my case but from the results I have read, it's worth trying.
The problem is that while others with the same computer and processor have been able to Undervolt, I am finding that my unit is persistently locked to such adjustment. The others have posts from 2018 to 2021 so I'm wondering if there is a hach or older BIOS that allows unlocking of the i7-8750H processor to such tuning?

 

[unclewebb]

You can modify a couple of UEFI variables to unlock CPU voltage control in many Dell laptops.

Undervolting 2020 Dell Laptops like the Vostro 7500 and More Tips to Improve Thermals, Battery Life, and Speed - Brendan Greenley

2021 Update: Based on post and Reddit comments, the approach to unlock undervolting works for a number of models, including the XPS, Inspiron, G5, 11th Generation Intel processors, and 2021 Dell models and other lines. If it works for you, please leave a comment below so others may know...

brendangreenley.com

The Dell XPS line have other throttling issues where the CPU might get stuck at 800 MHz. Reducing the voltage is not going to solve this problem.

 

[Errolw98]

Hello unclewebb,
Thanks for Your response.
I found this very thread in my searching and followed it to its end with the ability to change the values. My varname, varstore and varstorenames were, of course different than those shown in the link you have posted, as I was warned and suspected would be the case. I was able to change the indicated switch values from 0x01 to 0x00. The extra digit was unexpected but I went with my instinct on the value.
Both Intel XTU and Throttlestop 9.4 still have the Core Options locked out as pictured. I was thinking about running through Brendan Greenley's routine again to see if the enable switches were changed although I received confirmation at the time and entered the "setup_var [VarStore] [VarOffset]" command in the booted grubx64.efi routine before leaving the UEFI routine. Seems a shame to be locked out of these powerful tools.

One thing I found that stopped a persistent "Current/EDP Limit Throttling, Yes - Time active 100%" warning in XTU was in the Advanced Settings of the Advanced Power Options. That was to move the Processor management-Maximum processor state-Plugged in: from 100% to even 99%. Although this produced significantly lowered CPU GHz and score values in the Benchmarking results. This may alleviate the thermal load but appears to manually initiate a significant preemptive throttling and Core voltage reduction from the start. 3.9 GHz to 2.2 GHz and 1.251v to 0.900v at Idle. Along with that came an immediate thermal reduction from 70C average to 49C at the same 11% Idle CPU Usage directly before and after the advanced power reset. Using the live XTU graph at Bottom Left to monitor, the CPU Usage settles back to the 1-2% area after a couple minutes which reduces the Package temperature back to pre power setting levels around 42C at room temperature.
I suppose this is a form of "System Legal" undervolting or Frequency restricting but seems quite severe as opposed to direct CPU undervolt control and has a Significant impact on the Idle and Stressed or Benchmark CPU frequency and score as well. Temperatures do remain below 62C during Stress and Benchmark testing. I suppose the goal goal is satisfied with the Maximum processor state-Plugged in 1% reduction, if the goal is to simply reduce the operational package temperature.

 

[unclewebb]

Setting the max processor state to 99% is the same as checking the Disable Turbo box in ThrottleStop. Instead of doing this, you can try lowering the Speed Shift Max value in the TPL window. This gives you more control over how much turbo boost the CPU uses. Much better than all or none. Leave the Max processor state at 100%.

Not sure what procedure works best to unlock CPU voltage control. Dell might have changed something in their latest bios to block this trick.

 

[Errolw98]

Setting the max processor state to 99% is the same as checking the Disable Turbo box in ThrottleStop. Instead of doing this, you can try lowering the Speed Shift Max value in the TPL window. This gives you more control over how much turbo boost the CPU uses. Much better than all or none. Leave the Max processor state at 100%.

Not sure what procedure works best to unlock CPU voltage control. Dell might have changed something in their latest bios to block this trick.

unclewebb,
Thanks for clearing that up. You would think they would have enabled true %age levels for that. Looking through what IS available on TS now.