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.
EDIT: With that I don't want to downgrade Ati. I have nothing against increasing pipelines and clocks to the same architecture and calling it "next gen". In quotes because it's just an increment in the number. Both Ati and Nvidia never promised that "next gen" cards would be twice as fast as "old gen", just happened they followed that trend for some time lately. They don't "have" to deliver that kind of improvement, and if they don't deliver is not because they want to fool consumers. Anyway, anyone spending $300+ on a card without looking at benchmarks or knowing what exactly is buying, deserves to be fooled by the naming squeme IMO.