It's been a long time since I've run the Heaven benchmark, but I don't recall that much microstutter

Anyway, benchmarks are just benchmarks. I wouldn't focus on them too much if I were you.

Another thing, use the 259.32 drivers. They are the best drivers I've used so far for my 480s; especially for Crysis.

The 200xx drivers are actually quite immature at this stage, even the official ones. Nvidia is supposed to come out with the 260xx drivers in a few days, so hopefully there'll be some more performance improvements and bug fixes.