I also just did some tests of the new Asynchronous DMA engine in drm-next against a late 3.7rc kernel in Unigine Heaven
All tests are on:
AMD Phenom II x6 1055t
Radeon 6850 1GB
Linux Mint 14
OpenGL renderer string: Gallium 0.4 on AMD BARTS
OpenGL version string: 3.0 Mesa 9.1-devel (git-3392f2f)
S3TC is enabled
FP textures enabled
LLVM back-end enabled

http://openbenchmarking.org/result/1...SU-ASYNCDMAT32

It goes from 2.7 to 23 fps. Not quite a 10x increase. I'm out of time now, but after work I might run the full gaming suite and see what the overall improvements are.