Valve's distaste for Windows 8 has led the company to take on an increasing interest in Linux, and the new Valve Linux blog shows that, with some work, the Source Engine actually runs faster on it than it does on Windows. The company used a testbed with an Intel i7 3930k, Nvidia GeForce GTX 680, and 32GB of RAM to pit Left 4 Dead 2 on Windows 7 against Ubuntu 12, and the results are rather interesting.
At first, Valve's Linux port of Left 4 Dead 2 ran at only 6 FPS on the i7 machine, but after tweaking the game to make effective use of the efficient characteristics of the Linux kernel and OpenGL, the Valve Linux team was able to eke out a much higher 315 FPS. Using the same machine running Windows 7 and Direct3D, the same game ran at 270.6 FPS, or roughly 14 percent slower.
After optimizing the Source Engine for the Linux platform, Valve wondered why OpenGL was outperforming Direct3D at a technical level. Their research found that, on the same hardware, there are "a few additional microseconds [of] overhead per batch in Direct3D which does not affect OpenGL," indicating that Direct3D may not be as efficient as Microsoft would like developers to believe. There are still challenges ahead for the Valve Linux team, however, as the state of Linux graphics card drivers is still a tumultuous affair. The team has yet to work with AMD and Nvidia, but collaboration with Intel's engineers took place just last month.