27-Way NVIDIA & AMD Graphics Card Benchmarks On Linux
While Reaction Quake 3 isn't demanding on modern GPUs and any mid-range GPU can churn out several hundred FPS on the closed-source drivers, these results do show that the Radeon R9 290 was still running noticeably slower than even the GTX 680 -- under Windows, the R9 290 is generally competing in the GTX 780 space.
Prey is a similar story to Reaction and some of the other less-demanding workloads but where NVIDIA is still delivering the superior Linux experience with their closed-source driver.
Counter-Strike: Source is rather CPU bound on modern hardware, so the results aren't very interesting. For feedback on the Linux GPU benchmarks used, see Running Benchmarks On Other New Linux Games.