SDI Video Input and Layer Playback Performance

[samsc]

the problem is potentially related to issues that 1024x768 and 800x600 do not run at the exact same frequency - you would think they both run at 60.00HZ - . No they dont. at 1024x768 the display runs at 60.02Hz, and at 800x600 the display runs at something like 59.97Hz.
Very confusing, but this can and doees affect the performance of catalyst, which gets very confused by the slightly different refresh rates.

and there is an additional bug that is still not fixed by apple which does not report the correct frequency with these screens. when they run at different sizes

[Laura]

Well I'm happy to report that between the ATI driver and the adjustments to the screen outputs, and other tweeks to the SDI card drivers (turning off desktop preview, etc) I am getting smooth playback of two layers, one at 30fps and the 2nd at 28-30fps.
Graphics performance at the HUD is reported at 100% with the occasional small drop that comes back up to 100% before I can read what it is.
Are there other elements I could watch out for too boost performance at all?
Laura

[Laura]

Ooops, spoke too soon. There seems to be a conflict between the ATi system pref of "Vertical Sync" on and the SDI cards. If the SDI cards are off at the Catalyst Control window and Vertical Sync is on, I get good playback. If Vertical Sync is on and the SDI cards off, good playback. Turn all on, big problem.