The main problem is that the preveiw I do on the 0 key (old ram preview, not sure what is is now) does not work together with the preview on the spacebar???
If I cache the full range with the 0 key and later want to jump to a certain spot in that range. I go to the place in the timeline of interest and push spacebar to start playing from that time. But even thoe all frames is green and cached it still re-cache all frames before playingback smoothly.
In the first 2015 my experience is that after effect did not re-cache. It did not matter if you used the spacebar or 0 key to cache the frames. The green line meant the frames were actually cached!
I might have gotten it to work. For some reason the Mercury Transmit was turned of after the update and even thoe I have not activated the external output it looks I it did the trick. Need to use it a day or to to verify but looks like it fixed this problem.