Windows 10 vs. Ubuntu 16.04 NVIDIA OpenGL Performance
Xonotic with low image quality settings isn't demanding on modern GPUs at all, but goes to show that in the basic, CPU-limited cases that Ubuntu 16.04 with the proprietary NVIDIA driver is consistently faster.
When ramping up the Xonotic image quality settings, Windows came out ahead. This is due to Xonotic 0.8 and the NVIDIA Linux developers have already landed a change (that I believe should be present in Xonotic 0.8.1) for addressing that performance difference.
The synthetic GpuTest results aren't terribly exciting, but a few wins for Ubuntu 16.04 on NVIDIA 364.15 in cases like Plot3D.