An overclocker for the MyDrivers community with voltage modding altering and liquid nitrogen colling a speed as high as 1700 MHz core of the Radeon 7970, and 2000 MHz or 8.00 GHz (effective datarate ) GDDR5 memory speed.
That's 384 GB/s graphics memory bandwith really. The setup was able to run 3DMark 11 and 3DMark Vantage. The scores are pictured below.