NVIDIA GeForce 8: Linux vs. Windows
 

When it comes to binary display drivers under Linux, NVIDIA is
generally known as the company that's able to offer drivers that are on
par with their Windows driver. Unlike the known performance issues with
the ATI/AMD fglrx driver where it's not uncommon for the driver to be
50% slower than the Windows Catalyst equivalent, the NVIDIA Linux driver
has performed roughly the same if not faster in some cases. This has
also been true for the NVIDIA Solaris driver as the performance bastion
can largely be attributed to the shared driver code-base between all
NVIDIA-supported platforms (Windows, Linux, Solaris, and FreeBSD).
However, with the GeForce 8 series we have come across some unusual
issues that are limiting the performance of the GeForce 8 series under
Linux and Solaris. In this article, we have additional information on
these austere performance problems along with benchmarks showing the
frame-rate differences between Windows XP and Linux.

http://www.phoronix.com/vr.php?view=10563