Just spotted this bit of Info posted over at Guru 3D

It looks like the Radeon X700 will be an interesting card also. It's doing a 425 MHz core frequency and was running 860 MHz on it's memory. Have a look at the results. BTW I don't have a clue what test system was used and what settings where used in terms of optimizations and such on both cards. Still this could be a nice indication of what to expect of the x700.