"In my testing of Ubuntu 14.04 LTS with the Linux 3.13 kernel and Mesa 10.1 for the open-source graphics driver stack provided by Nouveau for NVIDIA GeForce graphics hardware, only the Fermi and Kepler GPUs are running reliably. While these newer NVIDIA GPUs are running stable with Ubuntu 14.04, the performance is still a wreck due to lack of reclocking."



Link: Phoronix