After I installed 10.6.1, my 17" uMBP doesn't play 1080p quicktime trailers if I use the 9400M chip. They play at really bad fps with QuicktimeX player. I use VLC to play them and they play as good as usual. So the 10.6.1 somehow broke the hardware acceleration part of 9400M for me. QuicktimeX player tries to accelerate the playback by hardware, which doesn't work, so it can't play them. VLC does it by CPU and it works. I didn't have this issue with 10.6. Anyone else with uMBP can test this out? P.S. If I use the 9600 GT, they play nicely on QuicktimeX player as well as before.