I just submitted a bug report on this, but thought I would also ask the forum as well.
I just upgraded to After Effects CS6 on a MAC OS X 10.6.8
My probelm is that for certain effects, the RAM preview is not clearing after I make a change. In particular, with "Particle Playground" I have the layer map as another composition. When I make a change to the layer image in its composition, the particle playground composition does not reflect the change and just stays the same.
If I then make another parameter change, the new layer will be there, but if I undo that change it goes back to the old layer map. If I reneder it out to a file it is fine and reflects all changes. However, the preview RAM system seems to be very buggy and very hard to clear out old RAM previews so that changes are reflected in the new preview.
The same thiings happens if I use an expression in particle playground. I change the expression and the preview does not change. Purging doesn't even help. I have been using this effect for some years, so I know what I am doing should not be a problem.
I see others have been having various problems with this new RAM Preview enhancement, which is great when it works, but is almost unworkable in some instances as I have mentioned.
If anyone has solved this problem, or has any ideas that would be great.
Thanks
John