Re: [Discuss] Speedstep on Celeron SU2300 - 20% more battery lifetime on Windows

[Arjan van de Ven <arjan@linux.intel.com>]

  On 9/6/2010 1:35 AM, Thomas Renninger wrote:
> Hi,
>
> I am adding lesswatts.org and linux-pm list.
> I expect you found out why you do not get frequency/P- states and it
> seem to be correct. On these lists, people can help you further
> to find out Linux vs Windows battery drain differences.
>
> If you have the same backlight settings, I expect C-state or graphics
> card must be the reason. There is nothing else than CPU or GPU
> that drains so much energy for being the reason of
> 20% more battery life time.
> Which graphics card and driver do you use (for nvidia/ati, trying the
> binary one for comparison, might show a big difference on a recent
> card)?
> Which C-state driver do you use (there is an acpi and intel_idle one
> with latest kernels):
> cat /sys/devices/system/cpu/cpuidle/current_driver
> I hope to be able to provide a c-state tool soon, for now you have to
> go through:
> cat /sys/devices/system/cpu/cpu*/cpuidle/state*
> to check which and how often/efficient C-states are used.

powertop will tell you exactly this

(and the next version will provide much much more detail)