I have a new 27 inch iMac - 3 gig dual core. I have FCP6 - latest version. I'm building a time line from DV footage - not HDV. Media is on a new LaCie 500 gig drive, connected via the FW 800 port. I've put a text element above a video clip. WHen I play back, the timeline stalls at the text location. How can I not be able to play a simple timeline with a 3 gig dual core machine? The drive is certainly fast enough for DV. What's up?