Ubuntu 12.04.4 vs. 13.10 vs. 14.04 LTS Desktop Benchmarks
Unvanquished with high and ultra image quality settings saw a drop in performance, similar to OpenArena, while the intermediate image quality level was less impacted. This drop in performance may be due to more OpenGL functionality being implemented within R600g and thus more rendering work compared to the driver in its earlier state.
The Xonotic open-source game with the R600 Gallium3D driver ranged from about the same speed as Ubuntu 13.10 to being some frames faster.