Re: [dwm] [OT] frequency scaling and power consumption

On Fri, May 8, 2009 at 9:08 AM, bill lam <cbill.lam_AT_gmail.com> wrote:
> BIOS support choosing a smaller multipliers to reduce cpu frequency.
> linux also supports frequency scaling such powernowd. Some google
> page said cpu throttling can not reduce power consumption. My
> experience is that it seems to lower temperature. If it can also
> reduce power consumption, I'm willing to save money by running cpu at
> half of its current frequency. Any idea.

My understanding is that power usage scales nonlinearly with CPU
frequency, and in particular having twice the frequency doesn't
require quite as much as double the power. So IF your OS can put your
PC into proper "sleep" states whent here's nothing to do (and that's
the big IF), the PC will use more energy in total by running at full
speed when you have work to do and then going into a sleep state
rather than taking twice as long to do the work at half the frequency.
So I'd expect you'd probably get less "energy usage reduction" from
getting rid of any services/device drivers/etc that stop the PC going
to sleep than from manually reducing the frequency. (If you're using
WSL, PowerTOP (

www.lesswatts.org/projects/powertop/

) is an attempt to provide a way to at most see what's causing
wake-ups, even if it doesn't necessarily show how to solve them.)
> --
> regards,
> ====================================================
> GPG key 1024D/4434BAB3 2008-08-24
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>

-- 
cheers, dave tweed__________________________
thin client vision reasearcher: david.tweed_AT_gmail.com
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