Originally posted by Iceman_IX 
 Honestly, just sounds like your power supply isn't cutting it and SWBF is bring it out. Can you do a full runthrough of 3dMark03? What's the brand/wattage/amps on each rail (12v, 5v, 3.3v) of your PSU? 
 There are very few reports of crashes in-game. Do you get an infinite sound loop as well?  
 Well I have a 450 watt powersupply that seems to have no issues with Doom 3 so I think thats ok.. 
 And as far as very few reports of crashes in game, try this at the lucasarts forum that has 85 reponses in 6 pages that all discuss the same issue we are having.  
http://forums.lucasarts.com/thread.jspa?threadID=6374&tstart=0)