Spec in sig. E8400 is at 3.6GHz.
1600x1200 at high, and it runs smooth as can be. Only "slight" choppiness is when there's a lot going on, but it's barely noticable.
I'm very impressed with how it runs on modern hardware, hats off to Codemasters for that (even though they optimized well but let bugs slip through!).
That's odd, it never gets choppy on my PC and I'm running it with just a single 4850 with a Q6700 clocked at 2.7Ghz and 8GB RAM.
Overlord is running with max settings 8AA 16AF at 1920x1200.