Fix power mgmt CPU throttling for better performance

[daniekr]

Since this is my first post I want to thank you all for providing much help both with this WS2012 installation and a WS2008 installation I did years ago. Now to the issue at hand:

After installing WS2012 Standard, updating everything and installing new drivers, I noticed that my performance in 3dmark06 was sluggish. I changed to High Performance plan in power management, and my scores drastically improved (actually better than on my fine-tuned W7 installation).

However I soon noticed that my CPU was running on 100% constant, drawing maximum power from my board. Two reason to avoid this is heat and voltage to your CPU. I’ve pushed my CPU to the limit overclock-wise, and I don’t want that high voltage to be constant on my CPU. But adjusting the min and max cpu-settings in the GUI power plan did not have any effect!

Power plans in WS2012 are documented here: Performance Tuning Guidelines WS2012

In short: “Balanced” is supposed to give performance on demand, but it caps your cpu (mine at about 50% although i believe 75% is right), “High Performance” locks your CPU at 100%. I used Prime95 to “demand” performance from my CPU.

To enable proper throttling I opened powershell and ran the following commands (they will adjust your currently selected power plan, I had High Performance selected):

Powercfg -setacvalueindex scheme_current sub_processor PROCTHROTTLEMIN 5

Powercfg -setacvalueindex scheme_current sub_processor PROCTHROTTLEMAX 100

Powercfg -setactive scheme_current

You might also want to disable Core parking.

Powercfg -setacvalueindex scheme_current sub_processor CPMINCORES 100

Powercfg -setactive scheme_current

For reference; my hardware:
CPU: Phenom II x4 955BE ([email protected])
MOBO: Gigabyte 990FX-D3
GPU: Asus HD 6870
RAM: 16gb Kingston Genesis ddr1600 (1600mhz 9-9-9-24 @ 1.6v)

Hope this helps someone.

[Author]

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