Linux gaming!
 

I've installed the Nvidia graphics drivers and RTCW: Enemy territory. it was pretty easy to get it up and running.

amazingly, ET runs flawlessly :)

I can't tell much about the performance, with my SD memory and a quadro2 MXR I'm getting sometimes under 20FPS in outside locations with low~medium detail and a resolution of 800*600

not bad at all... :)

Most opengl capable games (ut-clones, quake-clones) run flawlessly under linux.

In gentoo, it's extremely easy to install such games.
$emerge ut2003-demo
$/opt/ut2003-demo/ut2003-demo
et viola : )

Ati drivers are pure crap though, visual quality of my R9800 Pro is much lower than my GF2 Pro. : /

hmmm, isn't there anything like rivatuner for linux?

NVclock http://www.linuxnetmag.com/en/issue7/m7nvclock1.html

adjusting visual quality: check the README included.

(app-e) APPENDIX E: OPENGL ENVIRONMENT VARIABLE SETTINGS
=> edit /etc/rc.d/rc.local