Phoronix: NVIDIA GeForce 600 "Kepler" On Open-Source: It's Uselessly Slow

With the Linux 3.8 kernel that's presently under development, the open-source reverse-engineered Nouveau driver for supporting NVIDIA graphics processors has seen some significant changes. One of the late changes was enabling Kepler acceleration support. While there is now an "out of the box" open-source GPU driver that supports the GeForce 600 GPUs with 3D/OpenGL acceleration, it's incredibly slow.

http://www.phoronix.com/vr.php?view=18352