Well, I reckon your machine is not underperforming tbh.
FC2 is pretty CPU-heavy, I got a 10-15% increase in FPS on my E8400 going from 3 to 3.6 (just up your fsb to 400 and set your memory to 1:1 and instant 3.6. You might not need to adjust any voltages to get that).
Also the game runs better in DX10, again a 10% increase (I have benched FC2 in some detail due to my recent upgrade).
Also, you are running at 1600*1200, which is larger than my 1440*900, so I would expect you have slightly lower fps.
All in all your results sound about right, and I recommend at least a basic overclock to help you out, as well as running in DX10 if you can.