power saving computing - was Re: OT Re: ComputerGiving - CamLUG project

[Paul]

Sam Kuper wrote:
> 2008/10/21 Paul M <paul-clug at mansfield.co.uk
> <mailto:paul-clug at mansfield.co.uk>>
> 
>     By underclocking I can reduce power consumption by 20 to 25 watts, I
>     don't even notice the performance drop, but I can enjoy saving £180 per
>     year on electricity!
> 
> 
> Depending upon what you are serving, and to whom, you may not need to
> keep your server switched on all the time. If you only need on-demand
> access, you could in some cases set up your server to wake on LAN and
> keep it halted the rest of the time. This should reduce your energy
> consumption substantially.

good point, but I am also using it as a print server, mail server, http
proxy cache (ginormous squid spool), general linux toolbox, web page
testing, VPN termination, mp3 and media server (chipped xbox is client)
and more besides... so, it'd spend about 20 hours awake anyway. Oh, and
during

one thing I've taken a look at and failed, perhaps I'd need a custom
kernel, is getting power saving modes working - I can't get the clock
speed to dynamically change. I think but without investigating further
that the Athlon 32 doesn't offer much in this respect. My core1 Sony
laptop will drop its CPU speed by half, and $JOB's core2duo laptop will
switch each core separately to half speed too.