Sapphire recently updated their excellent TriXX software to support the HD7970 hardware. We used it today for our overclocking adventures.
We used TriXX to increase the core voltage to 1275, which allowed us to overclock the core by a whopping 25.3 percent to 1253mhz! As we mentioned earlier Sapphire have paid close attention to the cooling of this card, placing heatsinks on the memory. This helps push the 3GB of GDDR5 memory to 1,542mhz (6,168mhz effective).
These overclocked figures are the highest we have recorded yet, from any HD7970 solution.
This huge overclock pushes the Sapphire HD7970 Overclock Edition well past the GTX590 and almost to the same level as the last generation HD6990. The HD6990 only scores 81 points more. This really is an incredible result thanks to the class leading cooling solution Sapphire have implemented.