Nouveau vs. NVIDIA GeForce Linux Performance At The End Of 2014
The partially re-clocked NVIDIA GeForce 600/700 graphics cards could at least deliver very playable frame-rates for the extremely basic OpenArena game, but the performance still falls well short of the speed delivered by the NVIDIA binary driver.
The results shouldn't be as much of a surprise given that re-clocking support is the number one blocker right now from Nouveau achieving good performance, but unfortunately this is a difficult task and it will likely be a number of months before the re-clocking support for Kepler and other NVIDIA GPU generations is in good shape.