# FreeBSD tool for CPU undervolting



## UnnamedPlayer (Oct 16, 2011)

Hi!

Is there a tool for FreeBSD to undervolt an Intel SpeedStep compatible CPU similar to RMClock on Windows and linux-PHC on Linux?
I need such a tool in order to be able to lower the voltage of my CPU by ~0.25V to use my laptop comfortably. With stock voltages the CPU is constantly overheating and the fan is working at max speed at all times, not being able to cool it down.
My laptop is running stable with such settings for over 2 years now on both Windows and Linux and I wanted to give FreeBSD a try.
I know I could possibly patch the BIOS to fix the problem permanently but modifying it is quite risky.

The laptop is HP nc4010.
CPU is Pentium M 745 (Dothan, 1.8GHz, 2MB cache).

Thanks in advance


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## pbd (Oct 17, 2011)

Is powerd() what you're looking for?


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## UnnamedPlayer (Oct 19, 2011)

pbd said:
			
		

> Is powerd() what you're looking for?



Not really. Powerd appears to only control CPU frequency and I need something to adjust core voltage for given frequency.

For reference this is how you undervolt on linux:
https://wiki.ubuntu.com/UndervoltingHowto

Basically I need to adjust the VIDs (Voltage IDs).
Is it possible to do this on FreeBSD?


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