Performance is pretty good - it's just too late and comes at too much of a cost in terms of heat/noise/cost. Of course this is in the gaming domain where memory bandwidth currently plays a massive role. GeForceFX will really come into its own in DX9 titles that use complex shaders. Once this card has dev support it will really shine... as it will in non-realtime scenarios.
NV35 should be a lot faster. Low-K fab will yield a 20-25% raw clockspeed increase and a 256-bit memory should help bandwidth issues. The ASIC will incorporate many fixes/optimisations of the NV30 design and I expect nVidia will once again oversee PCB fabrication to cater for the *very* tight QC manufacturing such a board will require. If Cg has taken off by the Summer, NV35 should put nVidia back in the game - perhaps riding on the back of some crazy tech demos.
The big problem nVidia have now is NV31 - they wanted a 400-450MHz part to compete with the Radeon 9500P and possibly 9700NP. Current yields are struggling above 300MHz (I heard this independently and
CMKRNL seems to think the same thing), leaving a huge "hole" in nVidia's fall lineup. The silicon is extremely buggy, being a bastardised NV30 architecture with functionality patched up using fastex software shader hacks. Not quite sure what they are going to do about that one. NV34 is similar but a lot of the buggy NV31 functional blocks are simply not there.
A note for the camp that still insist the the Xbox project was not the one of the main reasons nVidia are currently behind in terms of product cycles - I am playing my "insider info card" here and saying YES - IT WAS, BELIEEEEEEEVE!!! Unless at SC they tell the troops that M$ is to blame in order to keep moral up and cover for shoddy management...
Flipper development was pretty much done when ATi aquired ArtX so it didn't constrain them at all in terms of R&D resources.
Xbox 2 will be different - this time M$ will have to earn a contract with nVidia if they want one, not the other way round. I'll stop now because I am starting to paraphrase from something sitting in my inbox...
MuFu.