Mesa 9.2 & The R600 SB Back-End Are Good For AMD APUs

The Reaction Quake 3 performance benefits greatly from the optimized OpenGL shader back-end.

Some of the Xonotic test runs also see performance improvements by simply setting R600_DEBUG=sb as an environment variable.

Mesa 9.2 is a nice performance upgrade for the AMD APU graphics performance while once Mesa 9.2 has been branched there will be further testing from other Radeon graphics processors. The R600 SB back-end also shows some noticeable performance benefits for some workloads and so hopefully some of the optimization strategies learned will end up being applied to the default shader back-end and the R600 LLVM GPU support.