When running the open-source Xonotic game at 2560 x 1600 with ultimate quality effects, the Radeon HD 7950 at its reference speeds was 25% faster than the Radeon HD 6950 Cayman at the same clock speeds. The XFX Radeon HD 7950 with its factory overclock was 28.5% faster with the 100MHz core bump and 125MHz extra out of the GDDR5 video memory. Lastly, when pushing the graphics card to its 1025 / 1450MHz overclock, it was 31% faster than the HD 6950 on Ubuntu 12.04 Linux.
Unigine Sanctuary also exhibited nice improvements with the Radeon HD 7950 on the fglrx 8.95.3 driver. However, the least-demanding Unigine tech demo did not get any greater kick out of the final overclock from 900/1375MHz to 1025/1450MHz.
Unigine Tropics was scaling nicely with the clock increases on the AMD Radeon HD 7950 graphics card. When the Radeon HD 7950 was pushed to its max with OverDrive, it was 46% faster than the previous-generation Radeon HD 6950.