I am running dual HD 6990s. The best drivers for me were 8.940.0.0 with included caps.
X7319 –> http://3dmark.com/3dm11/2548742
Everything else both newer and older scores in the low X5000 range. Yes, I had tried every single one. the increase is evident across the board, both gaming and benchmarks.
Anyone with similar setups had different experiences? Please post your results and driver versions.