Radeon RX Vega 64: AMDGPU-PRO vs. DRM-Next + Mesa 17.3-dev
The Team Fortress 2 performance was similar between operating systems.
Dota 2 with OpenGL is much faster on the fully open-source driver.
While RADV loses slightly with Dota 2 on Vulkan, but still good numbers considering RADV didn't even have working Vega support at launch and RADV remains a driver developed outside of AMD.
The open-source ET: Legacy and Tesseract games are much faster with RadeonSI.