The "R600" Gallium3D driver that provides open-source 3D/OpenGL Linux graphics support for AMD GPUs up through the Radeon HD 6000 graphics cards is becoming increasingly competitive. The open-source AMD stack isn't yet ready to overtake the proprietary AMD Catalyst driver in terms of raw performance or OpenGL compliance, but a lot of ground has been made up in recent months.
The biggest performance gain for the open-source AMD Linux graphics driver in recent months has been on the kernel side with the arrival of Radeon DPM support for being able to dynamically re-clock the GPU core/memory clock frequencies and voltages for the Radeon HD 2000 through Radeon HD 7000 series graphics cards. This is a big performance win and also leads to great improvements in power usage and heat output. The Radeon DPM support is still deemed experimental but is landing with the Linux 3.11 kernel and can be easily enabled through a kernel module parameter and updated GPU microcode.
The R600 Gallium3D driver has also matured a lot with the improvements found in the imminent Mesa 9.2 release. The "RadeonSI" Gallium3D driver also has, which supports the Radeon HD 7000/8000 series graphics cards, but there the performance is still a ways away from reaching the feature and parity of the R600 Gallium3D driver where the support spans from HD 2000 to HD 6000 series GPUs.
With the ever-advancing state of the open-source Mesa Gallium3D code and the stabilization of the near-final Linux 3.11 kernel, here's some new benchmarks of the Radeon HD 6000 series GPUs in our position. The tested HD 6000 GPUs were running the latest open-source driver code and the AMD Catalyst driver from Xubuntu 13.10.
On the Intel Core i7 4770K "Haswell" test bed the Radeon HD 6450, HD 6570, HD 6770, HD 6870, and HD 6950 graphics cards were tested. These are the HD 6000 GPUs in our possession while updated comparisons of older AMD GPU generations are forthcoming. The Linux 3.11 kernel and Mesa 9.3-devel (Git master) revisions were as of last week. Radeon DPM was enabled for all of the open-source driver testing while all other settings remained stock.