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Chris,
This reply is STRICTLY opinion on my part (please, no processor wars).
In my opinion, if your application has a lot of parallelism (as I suspect
given you are proposing a 100 node machine) then you are better off using
Intel processors, strictly because they have the most market support, and
thus are cheaper, easier to get, have more software available, and will be
easier to upgrade in the future (unless Intel decides to keep changing the
package every year <sigh>).
If you are already planning to use Myrinet, then the communication bandwidth
isn't really an issue related to the CPUs. Myrinet can be scaled quite
well with the number of processors up to a rather large number. Thus I am
suggesting that 200 P2's are probably a better bet than 100 Alphas at the
same cost (just an example, I'm not suggesting this is the actual cost ratio).
Plus NEXT year it will be easier to upgrade to the latest P2 (P3, P4, etc.)
than to upgrade the Alphas (considering ALL hardware AND software issues).
Being a "dyed-in-the-wool" Beowulf person, I tend to believe that the best
approach is to use a larger number of the most cost effective devices you
can get. Cost effective including all aspects of hardware and software, not
just CPU price and speed. For better or for worse, this is currently Intel.
Your mileage may vary.
Walt
--
Dr. Walter B. Ligon III
Associate Professor
ECE Department
Clemson University
