I am using a MB Core Duo 2.0GHZ. And when I select Unlimited RT, with both other options in Dynamic, whenever I make a change in the timeline or add transition or effects, an orange line would appear above the part I changed and when I want to play it in the timeline it would skip that part (it lags for a few seconds and then skip it). I am working with still images only, and a few LiveType titles. Are there any settings I am missing? Thanks a lot, Roco.