NVIDIA GeForce GTX TITAN: Windows 8.1 vs. Ubuntu 13.10 Linux
Right away from our testing the results are pretty much what is expected: the NVIDIA OpenGL performance for the GTX TITAN is more or less the same under both Windows and Linux. Past benchmarking at Phoronix of the binary NVIDIA driver has revealed the same that the performance in most situations is identical. This is not the case for all GPU drivers (including the AMD Catalyst driver with its Linux build lagging behind the Windows driver) and then, of course, there's the open-source GPU drivers that are generally performance-challenged.
The close performance of the NVIDIA GeForce GTX TITAN between Windows and Linux can be attributed to NVIDIA's driver model of having a largely shared, common code-base between all supported platforms: Windows, Linux, FreeBSD, and Solaris. There are just platform-specific "shim" layers and other OS-specific changes, but for the most part all of the hardware enablement, performance optimizations, and features are shared across platforms. This model allows for similar quality support across all operating systems with nearly identical features (with some exceptions like overclocking).