Here is a dude from the EA forums with a similar system:
CPU: i7 920 @ 4.021GHz
GPU: gtx 285 @ 702 MHz
6GB DDR3 1600
FPS (with fraps): about 25-45 depending where I am, probably averages about 35, 29 if i'm recording.
Sound about right? The beta isn't fully optimized so that is probably the issue. One thing that I read was that you can go in and change to DX9 to get a better performance. If you go into your documents and find bad company, you can change the DX from auto to 9 in one of the game setting files. Give that a whirl. I would also make sure HBAO is off. The devs recognize that is blows and they are optimizing it for the final release.