OpenGL performance

Faster Zombies! | Valve

Left 4 Dead 2 is running at 315 FPS on Linux. That the Linux version runs faster than the Windows version (270.6) seems a little counter-intuitive, given the greater amount of time we have spent on the Windows version.

I heard that already from different places. OpenGL seems to have a bit less of an overhead than DirectX. But then, who cares if it runnt 270 or 315 FPS. Can't see that difference anyways...