Previewing The Radeon Gallium3D Shader Optimizations
For Doom 3 at 1920 x 1080 with high quality settings, no real impact was found by setting "R600_DEBUG=sb" for the three HD 5000/6000 series graphics cards.
The Nexuiz performance changes if anything are very minimal because of the R600 shader optimizations.
The Reaction Quake 3 improvements were minimal in this hardware/software configuration.