AMD Kaveri: Catalyst vs. RadeonSI Gallium3D On Linux
Xonotic was running at less than half the speed of Catalyst when using the latest open-source Radeon driver code, but at least it's doing much better than the open-source driver state shipped in April with Ubuntu 14.04 Linux. Xonotic failed with the higher quality settings on Ubuntu 14.04 original due to AMD GPU LLVM back-end problems, but now Oibaf PPA has upgraded to the newer LLVM release that addresses these issues.