Right from the start with OpenArena we see the Nouveau driver still has a ways to go in being able to catch up with the official NVIDIA Linux graphics driver. Even though OpenArena is not demanding at all on a modern-day graphics processor, there was a measurable difference in performance between the GeForce 8800GT and 9800GTX when using NVIDIA's binary driver, but with the open-source Nouveau driver both graphics cards had ran at the same speed. On average, the NVIDIA driver was 6.74x faster than the current Nouveau 3D driver with the GeForce 9800GTX graphics card. With the GeForce 8500GT, the NVIDIA driver was 2.54x faster on average. The good news at least with the Nouveau driver is that with the GeForce 8800GT/9800GTX that OpenArena is playable at all resolutions, but the GeForce 8500GT did struggle a bit at resolutions greater than 800 x 600.
The Nouveau performance story is much the same with World of Padman. The NVIDIA driver continued to slaughter the Nouveau driver. With the NVIDIA driver the graphics hardware is not being fully taken advantage of or that the bottleneck is still within the Gallium3D driver itself where the NVIDIA GeForce 8500GT, 8800GT, and 9800GTX graphics cards all ran at close to the same speed. On average the GeForce 9800GTX was 8.76x faster with the proprietary driver.