How to undervolt your CPU (laptop/netbook users)

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How to undervolt your CPU (laptop/netbook users)

Postby ammon on Thu May 10, 2012 2:33 pm

This is for LMDE, UP4.

What is this?
This is patch that lowers CPU voltage (to some safe level), thus enabling your mobile computer to last longer on battery/be cooler/be quieter.

***Note, do not proceed if you don't know what are you doing***

I use Intel CPU, so I can't test for AMD CPU however you could Google around and check for your AMD cpu.

You will need build-essentials and current Linux headers.

1) First download phc-intel source:

2) Extract archive/open terminal

3) Build/Install

This is simple:
Just run
make dkms_mkdeb

and you .deb package should pop out, install it with gdebi od dpkg.

Now reboot, simplest way to load module.

4) Check is it working:

cat /sys/devices/system/cpu/cpu0/cpufreq/phc_controls

If you see something like:

Code: Select all
11:27 10:22 8:14 6:11 136:11

<- This are called VID's and they should be default values for first start

It is working, if not then something is wrong... Google or ask here.

5) Tune your CPU voltage:

There is tone of tutorials for doing this, just Google "Linux phc", or "Linux phc optimize".
I already know what VID's to use because I did this years ago on Arch Linux, and I still use same PC.

When you figure out what VID's you can use you use them at boot time via /etc/rc.local which is simple text file (you just add to it).
This is my rc.local:

echo "27 22 14 11 11" > /sys/devices/system/cpu/cpu0/cpufreq/phc_vids
echo "27 22 14 11 11" > /sys/devices/system/cpu/cpu1/cpufreq/phc_vids

I got my CPU stable and about 6-7 C colder, not bad.

More info:
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