I have a dual 2.0GHz G5 with 2.5 GB PC3200 RAM (4x512MB & 2x256MB). Once in a while the machine will just turn off. If I try to reboot, then it gets to the grey screen with the wheel and then just shuts off. It will only boot all the way if I reseat the RAM. I ran memtest in single-user mode on each pair separately and they all passed. It's not a huge deal as it doesn't happen that often (maybe once every other week), but it is kind of annoying. I'm not sure I can test the RAM by using different combinations since it doesn't happen all the time. Besides this the machine runs fine. Any suggestions? Thanks!