My guess is it's the CPU. Yes and I had scored near 14K with 256MB GTX SLI, which is only 500~1000 point difference from with GTX 512 SLI. From what I've seen, 14K+ score seems normal for GTX 512 SLI as of now.
P.S. Couple of findings:
1. Heatpipes on the cards get quite hot. (can't touch longer than 5 secs) It's strange because the NVIDIA control panel never reports over 60C (for the bottom card) / 65C (for the top card).
2. These are true power hogs. OK this is already known but I couldn't believe what I was seeing. I have a Monster power bar which reports power usage, and according to the reading my system + monitor (80W max) + speakers (120W max) draw 600W from the wall!! Of course that's when the system is heavily (read: near max) stressed but it's still unbelivable nonetheless. And my speakers were barely making any noise. Even after considering the efficiency of the PSU, my system should be sucking up at least 400W+ of power. Just something to consider (i.e. PSU) if you think of picking one of these.
lop