It has to have 800SP if it reaches 1TFlop with the 4850 unless there's a 1GHz shader domain we haven't seen, but that wasn't detected by the latest version of GPU-Z by w1z so I'm believing its 800SP's

P.S. die size isn't an indicator of how many SP's are in there since we don't know exactly how much each SP actually takes up... looking at the GT200 die shots, it doesnt even use as much as we think