This is the second compter I had installed it on. It's never been the rock solid application for me that others talk about. I tried the V5 demo. Now THAT seems rock solid. Much faster as well. Although, I really need to try V5I before I but. Come on Q2! Some quick specs: Dual Opteron 1.8s, 2 gigs ram, ATI 9800 128 megs. V5 seems to love this setup, whereas V4 seems to freak out when doing anything more than rendering a blank atmosphere.