We reported the Dell speeds of 650 MHz core and 2160 MHz memory a while ago and it looks like this will be the winning combination for Geforce 8800 Ultra. You can read the original story here.
Various sources have confirmed that the card will be very limited, that not every partner will have or indeed want them and that it will cost between $899 to $999.
These clocks are far from impressive, as EVGA and XFX has done 630 MHz with air-cooling already. The Ultra might be one to two per cent faster at this clock speed.
Maybe Nvidia have some hidden performance feature inside? Otherwise all this doesn't make any real sense at all. More shaders? We don’t have any more details at this point and the card might come out next week.