At work I'm on a MacPro (early 2008), and in it, there's an ATI Radeon HD 2600, which is outputting to two HP monitors. In addition, I have a Decklink HD Extreme card installed, which has several outputs and inputs. But none of these are being used at the moment. Still, FinalCut Pro 7 recognizes the Blackmagic card, and gives me several output options for Video Playback under the View menu.
Obviously, when I select a Blackmagic option, no video will be displayed - unless I plug a monitor to the Decklink card. But my question is: What if I choose the default option "Digital Cinema Desktop Preview", which fills my right screen with a full screen video preview - is the Decklink card helping the ATI card to drive the video playback at all - or is that pure ATI video playback? And what about real time video effects in FCP 7 - is the Decklink somehow contributing just by being installed in the system? Or would I have to connect something physically to the Decklink outputs to see/activate any of this GPU business?