Published over the night and already landing into drm-next for Linux 3.13 were the Nouveau DRM changes. While I have yet to come across any official announcement or email pull request, these changes do have re-worked power management and re-clocking support for the driver.
This is huge news since lack of adequate re-clocking has severely limited the driver's performance. See Nouveau vs. NVIDIA Linux vs. NVIDIA Windows 8.1 and Open-Source Nouveau Driver Remains Slow For NVIDIA's Fermi, Kepler.
Among the Nouveau DRM changes include user control of the GPU power state, sysfs interfaces for controlling the new power management code, automatic fan power management by default, many driver fixes throughout, and a lot of underlying work. When it comes to implementing GPU memory re-clocking one of the commits reads, "not even remotely ready for the vast majority of the world."
This new power management / re-clocking code does appear to cover GeForce 400/500/600/700 Fermi and Kepler GPUs, but none of the new code is enabled by default for this release aside from automatic fan power management. Will update when more information is available and will test as soon as the code lands in Linux 3.13 mainline Git, but for now you can browse through the code yourself from the Nouveau DRM Git repository.