Just played again tonight, got deep into some heavy fighting.
The Q6600 at 3 GHz can't even maintain 20 FPS in the busiest of firefights. Unacceptable. 30 FPS is already borderline unbearable, but 15-18 FPS on near-minimum graphics settings? That just won't do at all.
Haswell can't come soon enough, especially if it's the big performance jump out of Ivy Bridge that I'd expect of an Intel "tock" (new CPU architecture).
Meanwhile, one of my outfit mates with a recent i5 (didn't catch if it was Sandy Bridge or Ivy Bridge) at 6.3 GHz or so (water-cooled) says he gets 130 FPS on average. Seems a bit hard to believe for a game like this, but if it's true, maybe CPUs haven't been advancing quite as slowly over the past five years as I thought.