To overclock today we used Catalyst Control Center which while limited, allowed us to reach the maximum figures before calling in other tools such as TriXX.
As we experienced before, the core seems to be limited to around 900-910mhz, although this is reasonably healthy and shows safe margins at reference clocks. Any higher than 910mhz and the system would hardlock. If we pushed the memory clocks any higher than 1180mhz we could see artifacting on screen.
The overclock helped push the card past the last generation HD5850.