Here's a link to the youtube video. (http://www.youtube.com/watch?v=Uoo-B3PeyBc) Because of the refresh rate, you don't see near as much of the actual flickering. This time it happened while using After Effects CS5, but we've also had the problem with Maya, so this post is mainly to make others aware of the issue if they haven't upgraded to 10.6.4 yet.
My only guess is a serious video card driver issue on Apple's side and I have no idea how to resolve it short of downgrading, which is easier said than done. Also, my colleague found some Steam forums which describe the same exact problem.
This is happening on two machines so far. Both Mac Pros. One has a Nvidia GeForce GT120, and the other has a Nvidia Quadro FX 5600.
Edit: not sure why I posted this in Rendering.