so basically you say...
get another cpu ?
(yes i am looking for an excuse )
Here is your excuse. BC2 is a VERY demanding game. It eats CPU's for dinner and GPU's for desert. Everyone that I know who has a dual cord says this thing runs at 90%+. If you have a quad core it spreads that across all cores more evenly. And STILL is demanding on a quad core cpu. Look at this portion of a review regarding hardware and BC2. It shows an i7 920 vs and i7 975 using both an ATI 5850 and GTX 285. Notice what the difference is on even the highend CPU's. So your e6750 is just SCREAMING. The game has alot if physics which eats cpu utilization.
Also to put this in perspective for you. I have a 5870, which had to be sent back to ASUS for an RMA. In the mean time I am running an 8800GTX at 1680x1050. I turned off AA, AF, and HBOA. Everything else is HIGH, Vsync is ON, in DX10. I get a solid 60FPS and it actually looks REALLY good, I was impressed. The only kicker is I am running off an i7 920 @ 4GHz. I guarantee that is the only reason I am getting the frame that I am, if it was running on your e6750, I bet I would get half that.