NVIDIA Geforce 9800 GTX+, never failed me with Crysis, and the graphics in BF3 don't even look like a challenge (minimum settings). The game craps out when there's a lot of sound mostly, turning my view makes it worse. At one point there was so much sound going on that apparently the sound system crashed for a moment and everything went silent, and the game seemed to start running better, I think.
I've tried Hi-Fi, Headphones and Home Cinema audio settings, they all do the same thing.
I just updated everything after the game released.
I'll keep trying stuff, maybe I'm using too much RAM already, maybe BF3 hates me, maybe I need my money back. Who knows, I just don't need so much hassle at the moment.
Edit: Now I think it's a CPU problem. When I stand still everything is fine, GPU is used at about 80%, sounds don't stutter when I empty a clip. But when I turn round everything screws up, my GPU drops to 16% utilization and the temperature drops like a rock. Maybe it's the GPU screwing up when I turn and the CPU has to take over. I'm just rambling now, I don't know enough about this garbage to figure it out.