Hello guys, I recently upgraded my graphics card from HD5850 to a HD7950. Shortly afterwards i started messing around with it and read alot in OC forums about the hd7000 series and it's power. I got the sapphire vapor-x hd7950 OC with boost which is by default overclocked to 950/1250 mhz, the non-boost clock is 850/1250 mhz. I turned off boost, because the voltage was with 1,25v too high. I switched to the 2nd bios and manually overclocked with afterburner to 1 ghz @ 1,093v with unchanged memory clocks, the temperatures are around 55 °C at load and 29 °C idle. I can see some differences from 850 mhz to 1 ghz in some games, especially in Far Cry 3 and Battlefield 3 where you have almost 15% more perfomance. I might even go further and try 1150 mhz and see how that goes.
If you are also OC'ing your GPU or CPU, feel free to post your results here.