The wafers are same but unfortunatly nvidia has a much bigger chip. So yes exactly as i sayed. Nvidias alu takes much more area than ATIs anyway. And to add things together a 1024 sp GF100 would be a monster even on next shrink. They need already a shrink for GF100 if they want to get on ATI level.
I didnt sayed that they will double everything again or that it should be much faster, i just allege that ATI could pull out a 3200sp chip after shrink while nvidia can be happy with a shrinked GF100 with higher clocks, added transistors and die area to made it manufacturable. And this with a 6 month late on market.
Get on ATI level of what ? Die size ?
If GF100 is as fast as the known benchmarks show (granted they are from NVIDIA, so we need to wait for independent ones), the die size difference isn't a big problem, especially when GF100 is also targeted for a much more profitable market, which will help with the costs.