Just recently bought my macbook air 11in Ultimate. I tried to watch a 1080p HD movie recently and it lags every once in awhile, especially at certain action scenes and water scenes. The file is an mkv file that is @ about 11gb, and I am using VLC as my player. Do you guys have any recommendations as what I should be using to watch the HD movies? Playing using QuickTime lags even more than VLC. I thought the Geforce 320M should be sufficient enough to decode HD films. I have yet to try a 720p film yet.