How to reduce power consumption

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Revision as of 10:48, 24 September 2006 by Whoopie (Talk | contribs) (Sound)

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Reducing system power consumption will extend battery life, reduce system temperature and (on some models) reduce system fan noise. This page summarizes the known techniques for reducing power consumption on ThinkPad laptops under Linux. The power numbers given (in Watt) are very rough and model-specific.

System power states

CPU

Graphics

Hard disk

Spinning down the disk saves about 1W.

Optical drive

The optical drive consumes about 1W even when not accessed.

System fan

Consumes about 0.5W when running.

Wireless network

Consumes up to ~4W.

USB

Causes significant power draw due to bus mastering (affects CPU C-state). Disable by unloading modules, or unbinding the devices in sysfs.

Sound

Consumes about 0.3W. Disable by unloading modules or # echo -n 3 > /sys/class/sound/controlC0/device/power/state (replace 3 by 0 to enable again).

There's a experimental patch which enables the support of aggressive AC97 power-saving mode. In this mode, the AC97 powerdown register bits are dynamically controlled at each open/close of PCM streams. The mode is activated via power_save option for snd-ac97-codec driver. As default it's off.

Related toptics

External resources