You score is fine.
8821. My score is 8961 with my video card at stock. The 8800 GTS.
With my cpu at 3.4Ghz.
My numbers are close to yours. And they vary slightly every time.
It is perfectly normal. And remember thats only a 3D Mark score. If you games play fine, who cares
These people with 60 fps are they running identical components as you (not sli ?) and the same video drivers on the same os?