The GeForce 8800 Ultra appeared somewhere on the Dell XPS 710 page. It has 768MB GDDR3 memory, a 650MHz core and 1080MHz memory. The 384-bit memory controller and 128 unified stream processors are the same as on the GeForce 8800 GTX, but the GPU's clockspeed is 75MHz higher and the memory is clocked 180MHz higher.
This card is rumoured to be released by the end of May.