Hi,

This is really puzzling.

(Gateway 7330GZ laptop.. p4 3.06ghz - i know this isnt a battery-life-concious machine..but stil...)
I use windows and my battery lasts aprrox 2 hours. I've recently put fedora core4 on it.. and my battery gets totally used up in about 45-50 minutes... and im not actually doing anything with it.

wtf is goin on here!? I didnt think that the OS could make that much of a difference - because i wasnt aware of any battery saving things going on when i has windows installed.

Anyone got any ideas on this?

thanks for any replies!

That's odd, I actually found the opposite :P With my note book under windows I could only get about 15 min out of the battery. Under linux, that went up to 40 min. Go figure.

Ampex189

It has to be either the processor or monitor that's eating up that battery...in the case of the processor perhaps the fan is being run at full blast continuously? And the monitor, is the lcd brightness the same in both windows and linux? Apart from that i can't think of anything that uses up that much battery power. What i would do is find out the cpu temp in windows(when idle), then compare that to the cpu temp in linux, when idle. If linux is in fact running the fan unneccessarily, the reading should be lower in linux. Then we could force linux to turn off the fan once in a while. There are probably better ways of tackling the issue, but i can't say i know them. I'm not good at this...

The hdparm utility can be used to set power saving options for the hard drive. Try not to use the cd drive when running on the battery.

Monitor brightness has a large impact on battery life. Use dark colored background and a screensaver with minimal display effects, Don't use gl screensavers. Set dpms in xorg.conf so it'll cut itself off after a while.

Resource usage has an affect as well, Check that ACPI options for cpu and temperature are setup in your kernel. Setup a minimalistic wm to use when you run on battery. I did that with Fluxbox and ended up liking it so much it's my preferred wm.

I dont know why i didnt notice it earlier.... but in windows the laptop is quiet.. whilst with fedora it sounds like a jet. There must be a fan that has either been turned on or sped up significantly. The only problem is i have no idea how to turn that down / off!

(The LCD brightness dims when you unplug it which is working fine though.)

What you need is "Cpu frequency scaling". Try it on www.google.com/linux for more info.

Fedora kernel should have support for CFS as modules. Just download some daemon controlling the cpu frequency. I'd try them in this order: "powernowd", "cpufreqd", "cpudynd".