You still have pretty decent machine and I think quad core would be downgrade, don't have any statistics so more like a guess. I would wait till new Mac Pro, then sell it and get a new one
Westmere is the name of 32nm architecture which includes Arrandale, Clarkdale and Gulftown. Gulftown is the name of the six-core chip and there are DP versions of it, e.g. Xeon X5680
Depending on budget (assuming it's fairly limited, given the initial consideration of a Quad), the current Nehalem systems should be available at a discount, which will make them more attractive. Grab the fastest Octad possible, and it should serve the OP well (ideally improving as the software advances to be able to utilize Nehalem's architecture). 😉
Westmere is the name of 32nm architecture which includes Arrandale, Clarkdale and Gulftown. Gulftown is the name of the six-core chip and there are DP versions of it, e.g. Xeon X5680
Intel naming fun! Westmere EP is the "brand name" for the 5600 Xeons, Gulftown for the Core i7 ones and I've seen both used for the Xeon 3600s. Oh Intel.
Intel naming fun! Westmere EP is the "brand name" for the 5600 Xeons, Gulftown for the Core i7 ones and I've seen both used for the Xeon 3600s. Oh Intel.