I got my G5 on the 22nd, after some issues with the software update, I reinstalled OS X and it seemed to be working fine. Then the next day, I was converting something on iTunes from aiff to aac when it started going into sleep randomly, then waking up if I hit a button, only to go back to sleep a few seconds later. I tried unplugging my ipod, but that didn't help. I eventually closed iTunes and left on vacation for a few days. Yesterday I got back and everything was fine again. iTunes was working, I could convert, my ipod was fine. Then today, I was playing a game and it started again. Closed the game and it was fine.
I've also had problems with it freezing, at least three times. Any ideas what could be wrong? Thanks in advance.