For the bigger scenarios, CPU limitation would be more typical I'd say. I don't know what your budget is; while we're gradually implementing more parallelization in the coming years it's still not something that will happen fast; to that extent it's probably still valid to favor CPUs which, for the same price, offer a bit more single thread performance. But where this might really become noticeable the CPU prices are also pretty high, so this may be an entirely academic debate for you.
Personally I'd be tempted to try out the new AMD CPUs combined with a matching AMD GPU, and be it just to send a message to Intel to get their act together. Their price levels appear to be very attractive.


Visit the home of Steel Beasts!
...the ultimate armor sim...