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

[Paul]

Mark Wyatt wrote:
> Don't look forward to that £180 too much: 20 Watts * £0.92 is more 
> like £18.40 than £180 (although you'll be lucky to be paying as little 
> as 10.5 p per kWH for an uncapped electricity contract, these days). 

d'oh, when I originally worked it out more roughly, I got the right
answer, didn't have enough caffeine! I must have been thinking of the
total power consumed by the system before I started underclocking!

> Yes, the chipset for the Atom chip really is distinctly sub-optimal; it
> is just an existing, fairly coarse geometry, chipset with no particular 
> pretensions at power saving; it would be nice to hope that for the 
> next revision they do something more appropriate. 

the "poulsbo" chipset is said to be much better, not entirely sure why
it's not been widely adopted. perhaps because existing PC and laptop
makers didn't want to produce a completely new system design?
http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3276&p=16

> Note also that some UPSs tend to run a bit warm, which isn't exactly 
> helpful; I suspect that the energy efficiency figures don't look 
> particularly great at low loads, but it probably depends on UPS arch.

I've an APC Smart-UPS SC1500, load is 18% (270VA), current measured
externally is 1.5A (~350VA), so, I guess I am losing about 80VA. Not
sure of the power factor, but worst case is I am losing 80W. Not so good :-(
I get about one mains drop out a month typically averaging up to 20s,
and it doesn't return cleanly which is the big problem, hence why I
bought a UPS.