Getting underway with Doom 3, for all of the GPUs except the sluggish Radeon HD 6450 graphics card there are significant performance gains with the yet-to-be-released Linux 3.5 kernel. The Radeon HD 5750 frame-rate goes up by 33%, the HD 5830 is up by 25%, the HD 6770 is up by 25% as well, and the Radeon HD 6870 ends out with a 38% performance boost when switching to the Linux 3.5 Git kernel.
The Lightsmark test profile also shows dramatic performance gains for the Radeon DRM driver when using the Linux 3.5 kernel. The only exceptions here were the Radeon HD 5830 and Radeon HD 6450 graphics cards not showing any boost in performance. The HD 5750 and HD 6770 frame-rates went up by 24% and the HD 6870 "Northern Islands" GPU was faster by 29%.