Nouveau Kepler On Linux 4.6 vs. NVIDIA's 364 Proprietary Driver
While the manual re-clocking is able to help out the Nouveau's performance substantially, even for the OpenArena game the performance remains a great deal behind the proprietary driver. The card most competitive in this case was the GTX 680 relative to the binary blob's performance.
OpenArena is the most basic Linux game test used in this article.
With the Tesseract game, the re-clocked Nouveau driver remains a great deal behind the proprietary driver at least with the Linux 4.6 and Mesa 11.3 code. The GTX 680 remained most competitive with Nouveau compared to the binary driver's performance.