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AMD's Six-Core Istanbul Opterons
EconolineCrush writes "AMD's latest 'Istanbul' Opterons add two cores per socket, for a grand total of six. Despite the extra cores, these new chips reside within the same power envelope as existing quad-core Opterons, and they're drop-in compatible with current systems. The Tech Report has an in-depth review of the new chips, comparing their performance and power efficiency with that of Intel's Nehalem-based Xeons. Istanbul fares surprisingly well, particularly when one considers its performance-power ratio with highly parallelized workloads."
the real news here is not the extra couple cores, but coherency snooping. this feature will make 4/8s machines far more attractive; it doesn't hurt that with 48 cores and 32 ddr3/1333 dimms, you have quite a monster. _and_ incidentally something that Intel can't currently answer.
there's no question that nehalem has put a serious dent in the market, but Intel's going quite slow in rolling out higher-end products. yes, a nehalem socket delivers about 50% more bandwidth than a current opteron socket, but show me the 8s nehalem machines. nehalem-ex is coming, but how soon and at what price?
one thing I haven't seen is any attempt to measure real SMP performance on new-gen chips. I don't mean something like Stream or VMs, where there is no real sharing inherent to the workload. how long does it take to exchange a _contended_ lock between cores (in the same socket vs remote)?
finally, the real question is whether there is actual demand for more-core chips. I'm in HPC, and we always want more, and throw good money. but it has to be smart more - the 6-core core2, for instance, was just asinine because even 2c core2 is drastically memory-bandwidth-starved. nehalem-ex seems quite promising, but if it's cheaper to cluster dual-socket machines rather than pay the premium for 4s's, the 4s market will be stunted and less successful in a self-fulfilling way...