It's your processor, most likely. I had a 4600+ with my 9600GT, and my 3dmark06 score was 8135. Just with a CPU change to the 6000+ (65nm version), it went to 9229. With the 4850, I'm sure it'd be noticeably higher (maybe 10K?).
How do you explain the artifacting in the opening advertising in Crysis? The games runs fine at and after the Crysis menu though. Im updating to an intel board and Q6600 soon so Ill see if its the CPU or not.
What motherboard did you get?