With this testing the GeForce 9500GT, GeForce 9800GT, and GeForce GTX 460 were benchmarked from the stock Ubuntu 12.10 driver stack -- Linux 3.5, Mesa 9.0, xf86-video-nouveau 1.0.2 -- at the default boot speeds. The NVIDIA 304.43 driver was then obtained from the Ubuntu archive and benchmarked when the graphics cards were all operating at their rated clock speeds and then when underclocked. To match the Nouveau driver clock frequencies, CoolBits was enabled with the NVIDIA driver and then manually underclocked to the boot frequencies as reported when benchmarking Nouveau. The only exception here is that this can't be done for Fermi/Kepler graphics cards as CoolBits/overclocking is not supported on the newer GPUs under Linux.
Only three graphics cards were used in this stock Ubuntu 12.10 comparison since unfortunately the Nouveau driver still has stability and performance shortcomings even when running at the boot speeds. While the GeForce 8 series tends to be stable overall for Nouveau, when tested on the Ubuntu 12.10 stack, the GeForce 8 graphics cards were very problematic and ended locking up the system at various points through the OpenGL benchmarking process. All benchmarking was handled via the Phoronix Test Suite testing software.
Coming up soon will also be a larger Nouveau comparison when adding in the Linux 3.7 + Mesa 9.1-devel software.