How to reduce power consumption
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.
Contents
System power states
CPU
Graphics
- How to make use of Graphics Chips Power Management features
- Problem with high power drain in ACPI sleep
- Rovclock
- Reduce LCD brightness (~1-4W difference)
- Disable CRT output (~0.5W difference)
Hard disk
Spinning down the disk saves about 1W.
Optical drive
The optical drive consumes about 1W even when not accessed.
- Eject the UltraBay optical drive, or just turn off its power supply (i.e., run the appropriate eject script but leave the drive inserted).
- Reduce the spinning speed of the optical drive.
System fan
Consumes about 0.5W when running.
Wireless network
Consumes up to ~4W.
- Activate power saving on the wireless network card
- For Intel PRO/Wireless 2200BG Mini-PCI Adapter and Intel PRO/Wireless 2915ABG Mini-PCI Adapter, see instructions for the ipw2200 driver.
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=1 option for snd-ac97-codec driver. As default it's off.
Related toptics
External resources
- Power Management Guide from the Gentoo Linux documentation
- When/where/what for low power consumption? (thread on Linux-Thinkpad)
- 8hours of battery life on your lap(top) (ODP/PDF), a presentation by Pavel Machek
