Nouveau Kepler vs. Maxwell Performance On Linux 4.6 + Mesa 11.3-dev
To no surprise, the re-clocked Kepler cards run much faster than all of the tested Maxwell graphics cards on Nouveau that are bound to their boot frequencies.
It looks like the GTX 780 Ti re-clocking isn't yet fully working either as while the 0f performance state was reported, it doesn't look like the core/memory clocks actually ramped up that high considering how much faster the GTX 680 remained during the benchmarking process.
Re-clocking is necessary for getting decent performance out of the Nouveau (open-source NVIDIA) Linux driver for many games.
Team Fortress 2 is one of the games where re-clocking is needed to get half-way decent results.