3DMark 11 is designed for testing DirectX 11 hardware running on Windows 7 and Windows Vista the benchmark includes six all new benchmark tests that make extensive use of all the new features in DirectX 11 including tessellation, compute shaders and multi-threading.
After running the tests 3DMark gives your system a score with larger numbers indicating better performance. Trusted by gamers worldwide to give accurate and unbiased results, 3DMark 11 is the best way to test DirectX 11 under game-like loads.
If you want to learn more about this benchmark, or to buy it yourself, head over to this page.
With this synthetic Direct X 11 test, the HD7770 scores around 3,500 points which is around 1,000 points less than the HD6870. It is around 300 points more than the last generation HD6790 however.
In Crossfire, the performance just exceeds a single GTX580, although the differences are so minor it would be impossible to tell. The HD7950 scores a couple of hundred points more than the dual HD7770's.
Crossfire results are quite good as author said compared gainst more expensive 7950. much like the 5770 I owned, I had two and it was really good.