I played on a AMD Athlon 4800x2 that is like 3 years old and I had 69fps average on the CSS bench. At that point my 8500GT was causing the bottleneck. I also had 2 GIG DDR2 667. How much can the 200mHz make a difference in the same CPU family?
Nah...Run a 3Dmark...If you score less than 6000-7000 on default, it could be that your PSU is not supplying enough power to the GPU. This happened to me when I installed a 8800GT on a similar system. After testing with a friends powerful PSU, I started making decent frames and 3dMark results.