If you disable video preview in After Effects to the Matrox device, does RAM preview run in real time?
In After Effects CS6: Preferences > Video Preview, set Output Device to Computer Monitor Only. Matrox devices may also require you to disable WYSIWYG preview in their control panel.
When video preview is enabled, every frame is transcoded on the fly at display time to the format (dimensions, PAR, frame rate) requested by the device. This requires some memory and processor power and has an impact on performance. If having video preview enabled is in fact contributing to the issue, you can reduce the memory requirements of the frame (and therefore the processing power required) by reducing the RAM preview frame rate or resolution values in the Preview panel, reduce the project color depth, or disable color management in the Project Settings.
Worth noting here that After Effects CC 2014 (13.0) uses Mercury Transmit for video preview, instead of the older QuickTime and DirectShow technologies, and while it is still subject to the limitations above it provides better performance.
Thanks for your suggestion. I already had the Output Device set to Computer Monitor Only. So far, the only way I get real time RAM preview is by having the Matrox mini powered down.and Ray Tracing set to GPU. I've got one more session scheduled with Matrox tech support tomorrow. If we can't find a solution, I may just go back to CS5. Between the Matrox issue with CS6 AE RAM playback, AE not recognizing QuickTime and Premiere dropping frames (also a Matrox-related issue), this upgrade has cost me much time and angst. While I like CS6 otherwise, I have to go with what works. So fingers crossed we find a solution tomorrow. Thanks again - happy to hear any other suggestions. Cheers, Steve