Im using a 2010 iMac with a 3.2 i3 and 8GB of Ram. When I'm playing back a video in FCP7, there is a major frame rate drop. The video skips alot, but I don't get the error message or anything. I tried to fix the format to be in Apple Pro and I made sure that both my frame rate and rendering speeds were both at 100%. Any idea why I'm getting such frame drops?