Battery life question

alexmgarcia · 2010-08-08 11:44:16

Good morning,
I saw people saying that GNU/Linux uses more energy than Windows. To help increasing battery life they say to use laptop-mode, but it will never have the same life as in Windows. Is that true?
And by the way, some years ago there was a bug in laptop-mode that would kill the harddrive. Does that still exists?

Regards

KlavKalashj · 2010-08-08 12:06:58

I've also heard this, though I got nothing to back it up. I have also heard that Linux is 'killing' batteries, degrading their performance faster than other OS's. I would be happy to be proven wrong

karol · 2010-08-08 12:10:05

Battery life may depend on what graphics driver are you using: proprietary v. open source.
Bugs happen but usually they are reversible http://bugs.archlinux.org/task/20023

graysky · 2010-08-08 12:14:48

Running Arch/Gnome on my laptop for ages. Batt life doesn't seem more or less than when booted into XP when at work...?

alexmgarcia · 2010-08-08 12:19:06

graysky wrote:

Batt life doesn't seem more or less than when booted into XP when at work...?

In which does it takes longer to discharge?

karol wrote:

Battery life may depend on what graphics driver are you using: proprietary v. open source

Why does it depends on graphic driver? I have an Intel 945GM, so it will use the open source. Does it will use less energy?

litemotiv · 2010-08-08 12:27:46

alexmgarcia wrote:

Why does it depends on graphic driver? I have an Intel 945GM, so it will use the open source. Does it will use less energy?

Most of the open source drivers don't have full support for power saving yet, so in idle situations they don't scale down as well as they do on windows. Same goes for other drivers, like wifi etc. I'm not sure how the current situation is for Intel 945GM though.

You can find more information on powersaving here: http://www.lesswatts.org/index.php

Personally, i don't really notice much difference between linux and windows, but i might be biased.

alexmgarcia · 2010-08-08 12:37:49

litemotiv wrote:

Most of the open source drivers don't have full support for power saving yet, so in idle situations they don't scale down as well as they do on windows. Same goes for other drivers, like wifi etc. I'm not sure how the current situation is for Intel 945GM though.

Thanks for the info.
Here is an interesting comparison: http://www.myasuseee.com/windows-7-beat … tery-life/

fredre · 2010-08-13 06:01:10

This may not be the same "battery life" as you are talking about, but lithium ion batteries will lose their ability to hold a charge if kept fully charged often. Because of this, its a good idea to set a charge threshold, so the battery will stop charging once it reaches, say, 85% instead of going up to 100%. This can have a huge impact on extending the life of the battery. (laptop batteries aren't cheap!)

Unfortunately, most laptop makers don't provide drivers to do this for Linux (although they all do for Windows). In fact the only one that does, to my knowledge, is Thinkpad which has the tp_smapi driver.

orph · 2010-08-13 18:47:30

If you're about to reduce your PC's power usage, I would suggest you try setting CONFIG_USB_SUSPEND (the kernel setting to autosuspens unused USB ports) and to try a tickless Linux kernel.

In any cases, litemotiv indeed posted a must-read link about Linux powersaving: http://www.lesswatts.org/index.php

TigTex · 2010-08-14 00:16:16

When I compare powertop with windows multimeter i see a diference of 0.5w in power usage (windows uses less power). And that happens whatever I do. In real life it means something like 10min of my 8 cell batery (up to 4h uptime). This comparing to windows 7.
I'm using laptop-mode-tools pretty well tweaked and all powertop advices.
What do I think about this?... nothing, 0.5w is minimal

Last edited by TigTex (2010-08-14 00:17:09)

Google · 2010-08-14 05:23:35

I'm pulling 5 hours and 30 mins with Arch on a 6 cell battery

kokoko3k · 2010-08-14 08:25:35

I managed to tweak my asus 1005HA down to 6.7W, which is giving me more than 10 hours of life time when idling.
Asus advertise that value for WinXp, and just 8 hours for ubuntu (can't remember what version).
I didn't tried win7, but i've seen some tests comparing it to xp, and xp seems to be the winner by about 25minutes in idle.
It is clear that some user tweaks are needed under linux, but they gave me very good results, i'm veri satisfied.
(note that i've no powersaving issues with the gpu driver)

@Orph:
Isn't tickless kernel the default in archlinux?

Last edited by kokoko3k (2010-08-14 08:31:04)

habbe · 2010-08-14 15:24:42

Making valid comparisons is actually pretty time consuming, but I think that with my TP X61S Windows XP uses significantly less power. In Windows without wifi it says 8-9 watts, with Arch it is 10-11 Watts (similar screen brightness). Though I haven't checked whether windows is underestimating the power usage.

Powertop is suggesting nothing anymore for me, and yes I think arch default kernel is tickless.

A few things can at least make a difference, the graphics driver and wifi driver both have features unavailable in Linux.

lswest · 2010-08-14 20:45:46

I've got an Asus UL30A, and I have the same battery life in either OS (Win7 VS Arch, both 64 bit). The battery life is between 10 and 12 hours for my normal usage (with speakers or headphones and wifi it's around 10, without either, it's closer to 12 hours), which is the same as windows for me. Powertop estimates power usage around 8-9W, which I believe is the same as in Windows (Haven't checked for a long, long time). This is with just pm-powersave custom scripts to dim screen brightness and enable/disable bluetooth, acpid and acpi-support (from the AUR). I found laptop-mode-tools to not actually change settings on my computer, which is why I replaced it. If anyone is interested, send me an email and I'll give you a thorough listing of my scripts.

I've added my scripts and setup to the wiki here: http://wiki.archlinux.org/index.php/Asu … owersaving

Last edited by lswest (2010-09-02 16:35:21)

Arch Linux

#1 2010-08-08 11:44:16

Battery life question

#2 2010-08-08 12:06:58

Re: Battery life question

#3 2010-08-08 12:10:05

Re: Battery life question

#4 2010-08-08 12:14:48

Re: Battery life question

#5 2010-08-08 12:19:06

Re: Battery life question

#6 2010-08-08 12:27:46

Re: Battery life question

#7 2010-08-08 12:37:49

Re: Battery life question

#8 2010-08-13 06:01:10

Re: Battery life question

#9 2010-08-13 18:47:30

Re: Battery life question

#10 2010-08-14 00:16:16

Re: Battery life question

#11 2010-08-14 05:23:35

Re: Battery life question

#12 2010-08-14 08:25:35

Re: Battery life question

#13 2010-08-14 15:24:42

Re: Battery life question

#14 2010-08-14 20:45:46

Re: Battery life question

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