Following on from the Nouveau vs. NVIDIA comparison using the latest code and the AMDGPU/Radeon vs. Proprietary Driver benchmarks on the latest code, here are some Radeon vs. Nouveau results using the Linux 4.5 kernel with Mesa 11.2 Git code for a bleeding-edge experience. The NVIDIA hardware tested for this article included the GeForce GTX 460, GTX 550 Ti, GTX 650, GTX 680, and GTX 780 Ti. With all of the NVIDIA GeForce 600/700 Kepler graphics cards, they were re-clocked to their highest power-state manually prior to testing. Unfortunately, there still isn't any working GeForce 400/500 Fermi re-clocking support with this open-source driver.
On the red side was the Radeon HD 7950, R9 285, R9 290, and R7 370. The same Mesa 11.2 + LLVM 3.9 SVN snapshot (via the Padoka PPA) was used for the benchmarking process. The Radeon R9 Fury was left out from testing on the AMD side since when starting this testing on the Nouveau side I was using a mainline Linux kernel that didn't have AMDGPU PowerPlay built into the kernel, thus there wasn't re-clocking with the AMDGPU driver. The R9 285 results were left in but it's just showing the slower experience albeit what's provided out-of-the-box on Linux 4.5 unless rebuilding your kernel with the AMD PowerPlay Kconfig and then setting the amdgpu.powerplay=1 toggle. Another item to note on the red side was the Radeon HD 7950 remained very unstable and wasn't able to complete most tests. The R7 370 was also running into an occasional crash.
All of the OpenGL Radeon vs. Nouveau benchmarks in this article were driven in a fully-automated and standardized manner using the open-source Phoronix Test Suite benchmarking software.