First, Nvidia is "skipping" the 55nm process for the GTX200 series cards to go right to 45nm process? This means significant arch changes, since there is no way they can cram all the GTX200 series shaders onto a 45nm process. I wager yields will be low if they rush things just like they are for the GTX200 series and hence expensive. Second, if you believe the OP, GDDR5 with a clock of 2000MHz is actually 8GHz, a pretty substantial leap considering how new GDDR5 is. Third, no business lets the other side do anything. If Nvidia had a better card they would release the better card. From a business perspective, you never let up. That ATI has a great combo of cards with the 4850/4870 right now, and you can bet that Nvidia isn't happy about it. There stock has taken a pounding, their sales projection was lowered from $1.2 billion to $850 million, no profit making company would ever let another competitor do that if they could stop it.
While this is an entertaining rumor, some of the "projections" seem a little optimistic.
this doesnt look al that impossible to me, rly.