[Beowulf] power consumption for IBM J20 blade or Apple Xserve?

[Mark Hahn]

Hi.
we're looking into building a number of clusters, some of which 
have serious power constraints.  rather than just biting the bullet
and buying fewer dual opteron/xeon nodes, we'd like to consider 
lower-powered processors.  as it happens, those clusters will focus
on cache-friendly FLOPS; this makes the PPC970 look especially attractive

the IBM PPC970fx is rated at 24.5W dissipation at 2.0 GHz (theoretical 8
Gflops), but does anyone have actual measurements from systems using it?
I presume IBM's JS20 blade uses the fx chip; if so, does anyone have power
measurements for it?  IBM's website seems to be sanitized of anything 
past PHB levels of vapidity.

alternatively, does anyone have power measurements for Apple's Xserve?
Apple.com also has plenty of pretty marketing info, but little non-spin...

our config would likley be 1 GB/CPU, single small disk, and for one cluster,
a quadrics/myrinet/infiniband nic.

thanks, mark hahn.
(yes, I'm aware there are lower-voltage/power opterons available, but they 
compromise clock speed, cost noticably more, and are unavailable from most
vendors.)