[ltp] ACPI vs. APM (T41)

[Volker Braun]

Recently there were a few questions about the effectiveness of the power
management. Clearly, anectodal evidence ("my friend says his battery
lasts 5 hours") is not meaningful at all. So I actually measured the
battery life with various configurations. 

I find that ACPI is more power efficient that APM. In my
configuration, Linux with the experimental ATI Powerplay/DynamicPM
patches lasts 3h 9m, and Windows XP with IBM's own drivers lasts 3h
33m. So there is still some room for improvement, but the actual
difference is not that much.

More details (and a description of my configuration) are at:

http://www.sas.upenn.edu/~vbraun/computing/T41/power.html

Cheers,
Volker