I am trying to setup a new 8 core mac to run three screens with fcp 7. The mac is correctly set-up to run three LCD displays, with two identical graphics cards and no issues when running the usual desktop.
I have read that final cut will only utilise one of the graphics cards when it comes to selecting the preview screens, but the issue I have found is that it will not run the preview screen at all (other than making it black). In audio video settings I set FCP to run a desktop preview screen, then turned on all frames under the external video tab in the view menu, then get nothing but black when I try to play the timeline on the preview monitor.
However, when I unplug the third screen and just run two monitors, the desktop preview screen runs perfectly on the second monitor. Anyone know why this is?