AMD used to have a stronger HPC presence, but the advantages that its Opteron processors had over their Intel Xeon rivals evaporated, And because of Opteron chip delays and an architectural shift for interconnects, Cray shifted from Opteron to Xeon processors with its latest XC30 systems.
AMD has had a few key HPC wins with earlier generations of Cray machines
How does one safely lower the TDP rating of Opteron CPUs? I am willing to sacrifice some power, but wish to keep stability.
I have a TYAN S4985 Motherboard with 4 quad-core Opteron 8380 processors in a very well-ventilated case. I bought fanless pure-copper coolers that came with no TDP rating. They are normally used on racks with Opteron 280s (TDP ratings of ~90W).