When running the Lightsmark OpenGL lighting benchmark, which is more advanced than the ioquake3/Qfusion-based games, the Linux performance is horrific in comparison to Windows. The Windows 7 x64 Professional SP1 performance is far better than Linux and the open-source Mesa driver stack. If averaging the frame-rates from 800 x 600, 1024 x 768, 1280 x 1024, and 1920 x 1080, the Windows average is 55 FPS while the Linux frame-rate is just 15 FPS. The Windows performance is 3.66x faster than Ubuntu. Windows 7 started out at 82 FPS at 800 x 600 while Ubuntu 7 was just at 21 FPS. This performance difference is devastating.
The large performance difference between Windows 7 and Linux wasn't isolated to just Lightsmark, but with the real-world and very popular Nexuiz game, the Windows 7 performance is multiple times faster. With the Nexuiz high-quality settings, GLSL is used heavily and other advanced features. This weighs down on the Intel HD 3000 graphics under Windows, but the Intel Linux Mesa driver stack is hit much more severely. On average, across the four resolutions, the Windows 7 Core i5 2500K graphics performance is more than four times faster than Linux. It is 4.17x faster to be exact. At 1920 x 1080, the latest Linux driver stack bottoms out at just 3.6 FPS while the Windows 7 driver is running choppy at 17 FPS, but still that is a 4.72x difference.