Hi fellow After Effects users,
Today I discovered something very strange, working on my new iMac i7 Retina running Yosemite 10.10.4 and AE CS6 (188.8.131.52).
Making a Ram Preview of a 30-second 1080p animation mainly containing shape layers and .AI files, previewing at half resolution, took normally about 1:18 minutes:seconds to render before playback.
But, when switching to another program, this rendering time went from 1:18 to 0:08... yes 8 seconds!
I double-... no triple-tested my results: purged the image cache memory, purged all memory, restarted AE, and everytime the ram preview rendering took an amazing speed boost when I focussed my Mac to another program while rendering.
So what you do is you press the enter key on the numeric keyboard to start the Ram Preview rendering, then cmd+tab to your browser, mail app or whatever and boom, a few seconds later your Ram Preview is ready instead of waiting for over a minute (in my case).
I guess something takes a lot of time for AE to display the results on a Retina Mac, maybe because OSX doubles the pixels because AE CS6 is not a Retina-ready program (OSX just blows up the program interface by 200%, looking pixelly).
This has nothing to do with pressing the Caps-lock key - or it did not affect anything in my case.
Hope this helps and... Adobe people you might have an explanation for this..?