i've used c2 briefly on my g3 266 with os9.2.2 and it seemed stable, but i mainly work in 10.2.1 and that is pretty rock solid. i get a crash in the texture room every once in a while. also i found 10.2.3 to give me problems with carrara, so i'm avoiding it for now. are you sure that you're using the most recent version of carrara? should say 2.1 on the splash screen when you launch it. btw, i really don't think you should give the app less ram. 200-500MB seems like what the program wants on a normal basis (i figured this by watching the process viewer in osx while rendering)