The german folks over at Hardware-Infos have gathered up details in reference to the current state of AMD's RV790, which is expected to be RV770's successor.

Although AMD is likely still getting a feel for sweet spots, at this stage we can tell you from the information given that a 975 MHz memory clock is being used (despite the RAM chips being rated for 1 GHz) and the core clock has been bumped up by 100MHz to 850MHz, but this bump has required a core voltage increase to 1.3v (from 1.23v at 750MHz).

Beyond that we still know very little, but it's likely AMD will choose to let loose a lot of information about this next generation top-end GPU in March when CeBIT is underway.