Quote Originally Posted by Shintai View Post
Istanbul have to beat Nehalem-EP first. Gulftown could potentially take Magny-Cours alone. Its a hotfix, not a solution to their lacking core performance parts. They need a new core design to solve the issue. And specially something like SMT in the serverspace.
SMT in nehalem costs a lot in terms of core logic die space ,it doesn't come free you know. One Nehalem core is 24.4mm2,one Shanghai core is 15.3mm2,a staggering 60% difference.So 6 Shanghai cores at the same clock as Nehalem would outperform it while taking up 91.8mm2 compared to 97.6mm2 for Nehalem design-so less total core logic die area for more perf. It's easy to see AMD opted for core count over SMT strategy with Shanghai.It's less expensive from R&D pov,easier to design and is easier to validate(you just add more already proven cores at the time your process matures).Downside with Istanbul is a need for additional L1/L2 caches but it should add only about ~9mm2 of additional space on the die(7.5mm2 per MB of sram in 45nm Shanghai design)

Nothing comes cheap,SMT is no exception.I expect that Bulldozer cores feature some form of SMT(or maybe even DSMT?),but until then Shanghai/Istanbul/M. Course will do just fine.