well what kind of cpu do you have? Per core Cpu Perf is far more important in this game as it doesnt appear to load balance correctly.
Well it's a first gen i7. But it's an i7 950.
I doubt that would cause much of a difference in performance seeing how it hasn't really bottlenecked anything for me till date.
The i5 3500k is quicker but not by much, and at the same time my GPU is quite a bit faster than his 280x.