No matter what I do I average 5-7 fps. I've tried it on every setting (windowed/full screen, all low/high settings and everything in between) and can't get it any higher.

computer:
model: p7-1074
Processor: AMD Phenom(tm) II X4 960T Processor 3.00 GHz
Installed memory (RAM): 8.00GB (7.75 GB usable)
System type: 64-bit Operating System

Windows 7
ATI Radeon HD 4200