Xonotic with low-quality settings doesn't make much of an impact on the results/
When pushing through higher-quality shaders, the shader back-end begins to show off. The Radeon HD 6570 and HD 6770 graphics cards showed a noticeable improvement in performance via the "R600_DEBUG=sb" option for the shader back-end optimizations.
The Unigine Engine on the open-source drivers is still rather problematic, but for the poor configuration it didn't yield much change:
For the common Linux OpenGL test-cases there isn't too much to get excited over with the initial shader optimized back-end for the AMD R600 Gallium3D driver but the results from some of the more demanding OpenGL games did show Vadim Girlin's back-end is capable of raising the Linux gaming frame-rates.