I have a Macbook Pro 13" Mid-2010 model and recently I purchased some HD content from the iTunes Store. However, I have noticed that the video lags or appears to stutter along when I pause and resume and in some wierd instances even right after I choose to play a particular video. All this happened using the iTunes app, both in 720p & 1080p resolutions, although 1080p is much more prevalent. Issue crops out wether I am using the built-in monitor or whenI have my Mac connected to a external display(more specifically HDTVs). But I tried playing back the video file using Quicktime and it never seemed to suffer the same issue. I wanted to know if anybody else have had problems like this on their Macs & specially my model? My system have all the minimum system requirements for both 720p & 1080p HD playback so that can't be it I think.