I've got some mp4 files here that are accompanied by DT4 sound files. For some reason, when I play these files with Quicktime, the video is pretty choppy. Playing with VLC, everything seems to run smoothly. Why is quicktime slow? I'd like to use iTunes to organize my movies and watch them with Quicktime but not if the 720P and 1080P movies look choppy I've got a SG33G5 with a Q6600 at 2.7ghz, 4 GB of RAM and a X1950GT video card (my system is a hackintosh). Do I need a new video card or is there something I need to do with the settings?