For just the Radeon HD 6770 and Radeon HD 6950 graphics cards, below are some results showing the scaling at the higher resolutions. These results are part of 1302133-FO-UNIGINEAM41 on OpenBenchmarking.org.
At 2560 x 1600, the Radeon HD 6950 GPU was only pushing out 17 FPS while the Radeon HD 6770 was down to 7 FPS. There's similar Unigine Heaven/Valley scaling results for the NVIDIA GeForce GTX 680 Kepler in this article.
