Question regarding PL1 and PL2 readings

[issdar]

Good morning and happy Friday!

I had a question regarding the PL1 Power Limit and PL2 Power Limit readings in HWINFO64. When changing the PL1 and PL2 power limits in either Intel XTU or Throttlestop it does not get reflected in HWINFO however I know it took effect as I can see the wattage readings change for CPU Package Power. This is on a laptop Lenovo Legion 7i with the Intel 10750h CPU. I also noticed that the PL1 Power Limit reading sometimes dynamically changes between 55watt and 85watt by itself. Most of the time however it stays at 85 watt and PL2 never changes from 107 watt. Any reason why the PL1 and PL2 power limits do not reflect the settings set from throttlestop or intel xtu?

 

[Martin]

Where do you check the actual PL1/2 values in HWiNFO?
Those values have two settings: static and dynamic.
Static ones are reported in the main window under the CPU node. These should not change during runtime, so they are not constantly monitored.
Dynamic values are reported and activately moniored in the sensors window.

 

[issdar]

Where do you check the actual PL1/2 values in HWiNFO?
Those values have two settings: static and dynamic.
Static ones are reported in the main window under the CPU node. These should not change during runtime, so they are not constantly monitored.
Dynamic values are reported and activately moniored in the sensors window.

Hi Martin,

Thanks for quick response! Here is an image of the PL1 and PL1 Power Limits I am referencing. The PL1 is dynamically changing but very infrequent. Most of the time it stays at 85watt. The laptop has a manufacture "balanced" and "performance mode with FN+Q keyboard shortcut. This will change PL1 Power Limit reading to 60 watts. No idea why it sometimes will dynamically go down to 55 watts. I noticed the settings in throttlestop takes precedence over Intel XTU, how does the Bios PL1 and PL2 limits play into the priority when using throttlestop?

 

[Martin]

I don't know what method Throttlestop uses to change the limits, but I think that the BIOS changes this dynamically during runtime (via ACPI) based on various factors (i.e. skin temperature limiters).
So even if you set a value in Throttlestop, the BIOS will override this when it needs to.

 

[issdar]

I don't know what method Throttlestop uses to change the limits, but I think that the BIOS changes this dynamically during runtime (via ACPI) based on various factors (i.e. skin temperature limiters).
So even if you set a value in Throttlestop, the BIOS will override this when it needs to.

So did a little more testing. Setting the PL1 and PL2 limits in Intel XTU does indeed change both PL1 and PL2 Power Limit numbers in HWINFO. Changing TPL in throttlestop does effect cpu package power readings but does not change PL1 and PL2 power limit readings. I noticed that whatever wattage I set PL1 to in Intel XTU the reading from HWINFO is always plus about 8 watts for CPU Package Power sometimes. Does CPU Package Power reading possible include other things in that sensor reading? When throttlestop is open its TPL limits do indeed reduce CPU Package Power wattage and takes precendence over settings in intel xtu however the PL1 and PL2 power limits do not change in HWINFO. Throttlestop TPL settings will remain in effect even after program closes unless values are again changed in intel XTU.

 

[Martin]

Total CPU power can exceed the PL1 power limit for a limited period of time. There are other limiters like PL2, Icc,max, temperature. Exact settings depend on CPU model and platform settings.