When the resolution was increased to 2560 x 1600, the Catalyst driver was only 5.66x, 6.44x, and 6.35x faster for the Radeon HD 4830, Radeon HD 5770, and Radeon HD 5830 graphics cards, respectively. This though is not because the open-source driver magically performs better, but rather is illustrating the current open-source driver stack being bottlenecked with Nexuiz. The frame-rate is unchanged for these three graphics cards between 1280 x 1024 and 2560 x 1600 resolutions under the Linux 2.6.39 / Mesa 7.11-devel Gallium3D code where as the Catalyst driver frame-rate goes down by about 65%.
The Warsow game at 1280 x 1024 is at least playable across the three tested RV770 / Evergreen GPUs. The Radeon HD 5830 tops out at just under 80 FPS with the Gallium3D driver, but with Catalyst it is at 330 FPS, a 4.15x difference. The HD 4830 and HD 5770 were 5.44x and 5.60x faster, respectively.