I have a 2 GHz MBP with 2GB Ram. I also run XP through Boot Camp. I have no problem playing 1080p Quicktime trailers at the full frame rate under both OSX and XP. I recentley downloaded a 1080p Quicktime video of a Macbreak episode with Leo Laporte and Sal Soghoian (Apple Script, Automator Prject Manager). You can download the video from http://twitorrents.com/bm/detail/8/f0f7f01c30d1786f5c2e9f616d45d5ba1bcb0ac0 Under XP the 1080p quicktime video plays flawlessly at the full frame rate. However, under OSX the 1080p video only plays at half the frame rate (about 12 FPS). I have no idea why quicktime seems to be hampered under OSX. Anyone got any ideas?