What settings do you use?
I had my settings at:
1680x1050 (16:10 aspect ratio)
model, texture, shader and shadow detail at high
water: reflect all
HDR lighting at full
6x Anti-Aliasing
16x Antistropic filtering
Vsync: disabled
my framerate was 234.55
I have an AMD X2 6000+ at 3.4GHZ, with an 8800 GTS 320MB at 620MHZ, and 2GB DDR2-800 RAM.