My macbook air is rev b 1.6 ghz model, and recently I have found a serious problem: I have tried to use various of media playing software(including plex, mplayer, vlc, qt+perian, movist...) and none of these software could play a mkv 1080p HD movie smoothly. Even with plex, which is said to be the most efficient media player in mac os system, could not support 1080p movie well. So my buddies, what do you use to watch 1080p movies? Or you just install windows xp, vista or 7? Use kmplayer to solve this problem?