Phoronix: Ubuntu Linux Gaming Performance Mostly On Par With Windows 8.1

Given the recent release of Microsoft Windows 8.1, at Phoronix we took 13 different AMD Radeon and NVIDIA GeForce graphics cards and compared the performance between Ubuntu Linux and Windows 8.1 with the same hardware and set of OpenGL games/benchmarks. For AMD and NVIDIA graphics cards with their official drivers, the performance is largely similar between the competing desktop operating systems but there are some performance exceptions.

http://www.phoronix.com/vr.php?view=19257