I remember seeing a video of a new feature a number of years ago about being able to update certain layers and sections of the footage and aftereffects not having to RAM preview every layer again...or maybe just move some audio and not having to wait for that whole section of footage to RAM preview yet again.
It feels like Aftereffects has taken a step back in terms of efficiency and speed especially when it comes to RAM previews. In my experience anyway.
Also, when playing a RAM preview within 2 start and stop points I cannot just press play and it plays at 25fps (comp FPS). It will sometimes slowdown...only momentarily but it is still annoying when 1. It didn't used to do this years ago and 2. It shouldn't do this otherwise what is the point of a RAM preview if you cannot view it in realtime.
I realise there are aspects to take into considertation like PC spec etc but I have a machine with a very high spec. 2990WX AMD CPU, 64GB, SSD drives etc etc. If anyone from Adobe or the community can help me resolve these issues I'd be very thankful. At the moment this keeps happening on every project and it becomes very frustrating when you are up against a deadline!