Hmm I just thought of this: what if these cards have been optimized to run Ageia physics? With some sort of extra instructions and cache logic, and such. I mean that they are 8800s with better physics support and Tri SLI capable?
Forget about the naming, they are just refreshes, Nvidia had to increase the number because Ati did first, and because they are doing it again with HD4000, that is going to be the same with 480 SPs instead of 320 and faster clocks. And according to leaked info 50% faster than HD3000. Neither a great increase mefinks.