For those wondering how AMD's hybrid "AMDGPU-PRO" Linux driver stack compares to the latest pure open-source driver stack of the AMDGPU kernel driver and RadeonSI Gallium3D driver, here are side-by-side results for the Radeon RX 460, RX 470, and RX 480 Polaris hardware as well as the R9 Fury (Fiji) graphics card.
These are side-by-side results for AMD's two Linux drivers: the hybrid AMDGPU-PRO driver and then the pure open-source driver stack. The latest AMDGPU-PRO release was used during testing as was the open-source code in the form of Linux 4.8 Git, the latest linux-firmware binaries, and Mesa 12.1-dev Git obtained via the Padoka PPA on Ubuntu 16.04 LTS x86_64.
The RX 460, RX 470, RX 480, and R9 Fury were used for representing the latest Radeon GPUs. Due to AMD not yet open-sourcing their Vulkan driver (and RADV as the new Vulkan community effort for Radeon GPUs not yet being in shape for Linux gamers) that wasn't tested as part of this comparison nor was the OpenCL support with that being much better supported for now by their proprietary OpenCL driver.
Via the Phoronix Test Suite a range of OpenGL Linux game tests and other benchmarks were run with the four graphics cards on the two driver stacks.