Phoronix further investigated Nouveau's OpenGL Linux driver for NVIDIA graphics cards,
you can check out the analysis over here.
"As I began to share over the weekend, the community-created
Nouveau driver that's open-source and is written by clean-room
reverse-engineering the NVIDIA binary display driver, has reached a
serious milestone. For low-end NVIDIA GPUs, the Nouveau driver based
upon the Mesa Gallium3D architecture is now as fast, or even faster,
than NVIDIA's official proprietary driver."