With Nexuiz, Ubuntu 10.10 does not produce a playable frame-rate for the Radeon HD 4670 graphics card on the open-source drivers, but with Ubuntu 11.04 at 1920 x 1080 this game can run above 30 FPS. Of course, the Catalyst driver from last year is running at above 90 FPS.
For the last test today, the Urban Terror performance is also much greater in Ubuntu 11.04 than found in Ubuntu 10.10.
As you can see, if you are an open-source ATI Radeon user, there is a lot to be excited for in Ubuntu 11.04, particularly if you are a Radeon HD 2000/3000/4000/5000 series customer. The Radeon kernel DRM has improved a lot between the Linux 2.6.35 and 2.6.38 kernels and on the Mesa side, there are improvements with Mesa 7.10, plus the dramatic difference of the Ubuntu default going from classic Mesa to Gallium3D. This means faster performance, greater hardware support, and new features. Stay tuned for other Ubuntu 11.04 graphics in the coming weeks. Sadly though the open-source support is still far off from being able to handle advanced OpenGL workloads like the Unigine Engine or for GPGPU/OpenCL workloads. On OpenBenchmarking.org are also more Ubuntu 11.04 benchmarks. The Ubuntu 11.04 graphics stack is similar to what is to be found in Fedora 15 and others, except with Fedora likely using the newer Mesa 7.11-devel code.