The guys over at TweakGuides.com have posted a spiffy optimisation guide for Splash Damage's Enemy Territory: Quake Wars. Based on id Software's Doom 3 engine, there are probably a lot of tweaks you could carry across from the claustrophobic 2004 shooter. But, as far as the specifics are concerned, this guide is about as comprehensive as it gets.
So, if you're currently enjoying the beta, or maybe trying to enjoy it but the frame rate stinks like the intestinal wind from a curry-loving monkey, then you might want to give this guide a look-see.
Enemy Territory: Quake Wars Tweak Guide [TweakGuides.com]