Michael, I also had a 533 DP G4 and I too tried to play videos via my hard drive and more often than not, I couldn't. Since I work in video I determined that it was strictly a CPU issue and nothing else. A better video card made no difference. And I also could play DVDs without any problems. But DVDs off an optical player are not processed in the same way. You need a faster machine. It is that simple. YouTube was barely a gleam in the programmer's eye when the 533 was built. I bought a used DP Quicksilver for my home use and it does the job. I use a Mac Pro at work for any professional purposes. Bill