You gotta be kidding me. With a few tweaks you should be getting well over 8K on 3DM05....
I'm getting exactly 8K with an OC'd 7800GT (see sig) and no CPU overclock. So something is definitely wrong there. Nonetheless your initial result is not totally out of the range for a card of that type, but drivers play a part, BIOs settings play a part, you could definitely OC that bad boy and squeeze out another 10%....
The newest drivers sometimes don't boost performance at all. Quite the opposite in my experience.