Check my post from about 2 months ago. Several things you can do, #1 check top of timeline, any color other than gray will cause dropped frames. Red indicates as you know unrendered, however, green, will result in numerous dropped frames. #2 Hard Drive space, anything I belive you’ll need at least 30 GBs space (I’m sure I’m wrong about the requirments, but you can look it up) #3 Go to Larry Jordan’s website, look under maintenance. You can find out how to do the MAC verison of Defraging. Of course increase your RAM (no more than 2 GB of RAM necessary, however you can get by with 1.5) Hopes this helps So if too long.