Difference between revisions of "Undervolting CPU"

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(Better and more straightforward description of what is CPU undervolting.)
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It is a process where voltage to CPU is reduced in order to reduce its energy consumption and heat without affecting performance. Note that most desktop motherboards allow tweaking CPU voltage settings in BIOS as well.
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Undervolting is a process where voltage to CPU is reduced in order to reduce its energy consumption and heat without affecting performance. Note that most desktop motherboards allow tweaking CPU voltage settings in BIOS as well.
  
 
{{Warning|Misconfiguration of CPU voltage settings might result in permanently damaged hardware. You have been warned!}}
 
{{Warning|Misconfiguration of CPU voltage settings might result in permanently damaged hardware. You have been warned!}}

Latest revision as of 10:39, 5 June 2019

Undervolting is a process where voltage to CPU is reduced in order to reduce its energy consumption and heat without affecting performance. Note that most desktop motherboards allow tweaking CPU voltage settings in BIOS as well.

Warning: Misconfiguration of CPU voltage settings might result in permanently damaged hardware. You have been warned!

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Needs to be expanded. It could be that PHC needs to be merged here as well. (Discuss in Talk:Undervolting CPU#)

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.
  • #amdctl - a tool for undervolting K10 and newer AMD CPUs.

Tools

intel-undervolt

Intel-undervolt is a tool based on this article for undervolting Haswell and newer Intel CPUs using MSR and MCHBAR registers. In addition, it also allows to change power and temperature limits.

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:

Note: Looks like 'CPU' and 'GPU' values does not have any effect (at least on ASUS Zenbook UX430UQ laptop).
/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.

amdctl

amdctl is a tool for undervolting K10 and newer AMD CPUs.

Installation

The tool can be installed as amdctl-gitAUR.