[Beowulf] recommendations for cluster upgrades

[Mark Hahn]

> I'm currently shopping around for a cluster-expansion and was shopping
> for options. Anybody out here who's bought new hardware in the  recent
> past? Any suggestions? Any horror stories?

I think the answer depends on time-frame.  if you're bw-sensitive,
you go nehalem for the time being.  for the near future, I'm interested
to see how AMD's next-gen "istanbul" works out.  AMD obviously needs 
to break out past ddr2/800 - it would be kind of surprising if they 
went 6c/socket without some improvement.  AMD has made a big deal 
about the cache snooping, but I'm not sure how much it matters for 
the main market (2-socket).  if you're considering 4-socket, I'd 
certainly think about whether to wait for istanbul.

> We've been using Dell SC1435's with Quad-Core AMD 2354 Opterons @
> 2.2GHz. 16 Gig RAM.

2G/core seems to be fairly safe.  although it's overkill for a lot of 
users, ram is also pretty cheap - 6x 4G dimms for dual-i7 is probably
pretty sensible.