Open-Source NVIDIA Driver Approaches Stable State
Nouveau is faster than NVIDIA for the VDrift racing game, but don't compare the two drivers: the Mesa/Gallium3D drivers fail to properly compile the GLSL shaders for this game so there's lots of white blocks and other issues when using the open-source drivers.
Xonotic, the popular Nexuiz-successor, performed very well across the pre-Fermi NVIDIA graphics processors with Nouveau Gallium3D and was more than playable (100+ FPS) at the miniscule resolution of 1280 x 1024. Meanwhile nearly all the NVIDIA hardware backed by the binary driver alternative were at 200+ FPS.