Undervolting CPU
Undervolting is a process through which voltage to computer processors and components is decreased dynamically on run-time. It is a process within dynamic voltage scaling that enables conserving electric voltage to reduce energy consumption and heat produced by computing components without affecting their performance.
Overview
-
PHC - a tool to undervolt some old generation Intel and AMD processors. Not compatible with
intel_pstate
CPU frequency driver. -
#intel-undervolt - a tool for undervolting Haswell and newer Intel CPU using MSR. Compatible with
intel_pstate
.
Tools
intel-undervolt
intel-undervolt is a tool for undervolting Haswell and newer Intel CPU using MSR. This tool is based on the content of this article. This tool also allow to alter power limits and temperature limit using MSR and MCHBAR registers.
Installation
The tool can be installed as intel-undervoltAUR.
Configuration and usage
The following command prints in use voltage settings:
# intel-undervolt read
Now edit the configuration file /etc/intel-undervolt.conf
. Example config with undervolted CPU Cache by -100mV:
/etc/intel-undervolt.conf
... apply 0 'CPU' 0 apply 1 'GPU' 0 apply 2 'CPU Cache' -100 apply 3 'System Agent' 0 apply 4 'Analog I/O' 0 ...
Once you saved configuration file - test it:
# intel-undervolt apply
It will print Success if settings were applied. You can double check in use configuration using the following command:
# intel-undervolt read
Once you find stable configuration, you can also enable intel-undervolt.service
to make changes persistent.