NVIDIA 375.10 vs. Linux 4.8 + Mesa 13.1-dev AMD GPU Benchmarks
RadeonSI developers have worked on various optimizations for BioShock Infinite on Linux, but these results show the game is still running into a big bottleneck with the open-source driver stack... Especially with that bottleneck putting the cards like the R9 Fury and RX 480 as performing less than the GTX 950.
The RadeonSI driver with Counter-Strike: Global Offensive appears to hit a bottleneck at a lower frame-rate than the NVIDIA cards with the proprietary driver on the higher-end cards.
But at least CS:GO at 4K is more of a competitive race between NVIDIA and AMD on Linux.