How to improve laptop battery life?

[Mark Greenwood]

Next question...

Anybody got any tips on improving the battery life on my laptop? (Sony VAIO, Core II Duo, NVIDIA graphics) Under Windows (spit) I can get around 3 hours. Under Linux (of any distro) I'm lucky to get 45 minutes, which drops to under 30 if I switch the wireless on.

I've configured all of KDE's Powersaving features including switching compositing off and reducing the backlight level (using smartdimmer), setting the CPU scaling policy to 'Powersave', etc. I've set up laptop-mode to spin down the hard drive and enabled most of the other features relevant to my hardware. I've done everything powertop suggests but nothing comes close to addressing the problem. What is it about Linux that makes it use 300% more power than Windows, and can it be tweaked?

Thanks,

Mark