I just spoke with a Black Magic tech guy and he said there are no known issues with the Decklink/Multibride hardware and OS 10.5.2 and Quicktime 7.4.1. I’m running the Black Magic 6.6.2 drivers for Multibridge Pro. I’m updating now and will let you know my results.
2.6 GHz Mac Pro Intel Quad Core
7GB of RAM
ATI Radeon X1900 Video Card
Black Magic Multibridge Pro (Firmware v. 6.6.2)
Final Cut Pro v. 6.02
Quicktime v. 7.3
Motion v. 3.02
BCC v. 5.0.1