The professional applications and scientific computing market is big, not as big as the video game business, but the current number of professional and scientific applications taking advantage of CUDA after only a couple years is huge, they have an installed base way larger than ATI. If they can keep that base, as they likely will, the entire graphic design, movie production, animation, GIS, oil & gas industries and academia may shift to optimizing their tools for CUDA. I personally think they'd be better of designing for Open CL, so that they can use ATI or nvidia cards for GPU acceleration, it might not be as optimized as if it was specifically tuned for one architecture, but would hedge their bets. Considering we can all by the end of this year have maybe 20 Tflops with 4 x 5870 X2's on our desktops, it's amazing, what would four of these new cards be capable of?