I have a movie 1 hour 40 mins long where I have been replacing parts of the video with a powerpoint page with the audio from the video on it. Theres somewhere between 100-150 powerpoint pages and theres a cross dissolve eveytime the video goes to powerpoint and another when it goes back to video. Anyway I am almost done, maybe 15 minutes of movie to left to edit and iMovie is working EXTREMELY slow. Like theres a good 5-10 seconds of lag everytime I try to drag a clip or something, and I have to do lots of clip dragging to get each transition in perfect placement. Even just moving the cursor around the video theres at least a few seconds of lag. I went to another shorter project that was about 30 seconds long and it works fine. PLEASEEE, is there anything I can do so I can work at least at a tolerable speed?