ATI Radeon KMS vs. UMS Performance With Ubuntu 10.04

When running at 800 x 600 with the Urban Terror game that is also powered by ioquake3, the UMS and KMS performance ended up being the same at the lowest resolution, but the delta increased with the resolution. By 1920 x 1080, Urban Terror was 37% faster when kernel mode-setting was disabled.

With our final test, which was running the open-source VDrift racing game, the kernel mode-setting path finally led to superior performance. VDrift along the Radeon kernel mode-setting paths were significantly faster than with user-space mode-setting.

You can share your own test results and discuss these findings within our forums. Radeon kernel mode-setting can be disabled by adding radeon.modeset=0 to your GRUB boot options or adding options radeon modeset=0 to your modprobe configuration.