# maximizing battery life

## deathcon1

I have a Lenovo T61P, and after a few charge/discharge cycles I'm pretty confident in the power readings form the Gnome Power Manager.  Idle I'm using about 18w of power and under light load (1x firefox couple of tabs, amsn, that's it) and i'm using ~21w of power.  I'd like to see this reduced as much as possible as I only get about 2 hours on battery.  I'll have some more exact specs when I get home.

Hardware specs:

15.4" 1680x1050 display

nVidia Quadro 570m 512M (256MB onboard + 256MB system)

4GB DDR2800 RAM (2x SODIMM's)

160GB 7200 RPM harddrive

Intel 4165 ABGN Wifi card

Onboard bluetooth.

Also, not sure if it matters but my MTRRR's are screwy and I have to run a script to fix them.  Suggestions?  I do have a 160GB 5400RPM drive I could throw into the laptop but I was told 5400RPM to 7200RPM is about 1.5watt difference (I'm cool with that for the performance boost.)

Another point, I've head that reiserFS uses more power (via keeping the harddrive awake longer) then EXT3, however I havn't found any evidence to suport this.  I've also been debating whether XFS would be a better FS on a laptop for several reasons: 1 it buffers more to RAM so it won't wake the harddrive as much and, since the laptop is running on battery, the only time the system would be hard-halted (i.e. hold power button 5 sec) would be if the kernel paniced and the data in RAM would be lost anyways.  Is there a flaw to this logic that I might not be seeing?  Yes it's more aggressive in RAM but...i got 4GB lol. 

Too many also's. 

I've head rumours that KDE is easier on battery then Gnome (as Gnome seems to poll for a fair amount more data and collect statistics which are nice but generally unnessicary.)  Truth to this?

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## albright

look here: www.lesswatts.org/projects/powertop/

for many tips, tricks and info

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## kernelOfTruth

use the tricks on lesswatts.org and the suggestions made by the running powertop

 *Quote:*   

> Another point, I've head that reiserFS uses more power (via keeping the harddrive awake longer) then EXT3, however I havn't found any evidence to suport this. 

 

if you're brave mount reiserfs with -o noatime,nodiratime,commit=120  (writing stuff every 2 minutes)

other settings:

```
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
```

```
echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
```

```
for i in /sys/class/scsi_host/host*; do

         /bin/echo "min_power" >  $i/link_power_management_policy

done
```

and stuff for the VFS:

 *Quote:*   

> echo 10 > /proc/sys/vm/page-cluster
> 
> # default: 3
> 
> #
> ...

 

additionally use the compcache + tlsf patch for kernels and use via lzo compressed swap in your ram instead of on your harddrive

 *Quote:*   

> as Gnome seems to poll for a fair amount more data and collect statistics which are nice but generally unnessicary.

 

not really, only if you're using lots of applets which read out hardware & need to update their state to show differences (e.g. volume-manager, network-monitor, etc. etc.)

the DE with less load on cpu / battery would be openbox, fluxbox, ...

as filesystem I'd suggest default reiser4 or even better: reiser4 w. lzo1 (compression) it eats somewhat more cpu-power but also completes work much faster so there's less load on the hdd but more on the cpu 

you could also tweak your system with ldflags: --as-needed (needing less linked libs), etc. etc.

7200 vs. 5400 <-- on a laptop i'd take the latter because of the longer battery runtime, if you're using the laptop more as a desktop replacement take the 7200

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## deathcon1

I actually don't have a swap file at all, and havn't noticed need for one in any system with >2GB of memory. 

I'll try swapping the drives see if that makes a difference.  

What is this VFS stuffs?

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## carpman

Look at jfs this has low cpu/power usage, i have it on on my laptop except for /usr/portage and /usr/src which are reiserfs.

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