[Beowulf] /. Cooler room or cooler servers?

[Jim Lux]

At 04:27 PM 4/7/2005, Mark Hahn wrote:

> > One also needs to look at important ancillary issues like power 
> consumption
> > of the cache, bus drivers, etc.  And, of course, instruction stream 
> makes a
> > big difference.
>
>kind of obvious, don't you think?  when I said peak, I meant peak,
>and I'm quoting power dissipation measured at the wall plug (kill-a-watt).
>for these systems, running two compute-intensive programs maxes out;
>messing with memory or disks only adds a few watts (percent).

My point was that the "Superior Power Efficiency" kind of chart (no matter 
where the numbers come from) is really meaningless.  Simply knowing the 
basic technology level will tell you how many Joules/calculation you'll get 
to a first order.  Any finer refinement will be very, very implementation 
and algorithm dependent.


James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875