I have a 2007 Mac Pro, 2 2.66ghz dual core intel xeon, 1GB 667 MHz memory. I'm running FCP 7. I know I should have more RAM to be editing in FCP, but everything was just fine last week, and my playback was just fine smooth. I'm editing 1080p ProRes HQ. I went back to re-edit, and now when I play the sequence, I get the spinning beach ball 5 seconds in. Everything is rendered, but I still can't play it back smoothly. What can I do to solve this? I'm not looking to put too much more money into it at this point, but I am willing to spend $50 for 2GB more of RAM if that would help me get this edit done. Would that help? Thanks ahead for your help!