I always wondered also why you cannot play back footage like that in Premiere. Makes no sense at all.
This thread is useless without system details. This is the most productive version of AE that I have ever used on OS X 10.11.5 and Windows 8 running in Bootcamp on my Mac Pro. 3 machines - very few problems.
Jbrown432 - The reason AE does not run previews like Premiere Pro is that it is a compositing app that analyzes every pixel one frame at a time. The entire process is different than an editing app which plays back multiple streams of video. All compositing apps pre-render their effects. Premiere Pro pre-renders simple transitions - but it happens in real time. Throw two layers into Premiere Pro, add some effects that require rendering and PPro will not playback in real time until you render a preview. The preview is turned into a stream of video - a movie that lives in cache - so it plays back in real time easily.
AE is getting better. I expect more improvements in the future, but when you are doing compositing you have to handle the pixels in a different way than you do when you are editing.
I understand, but you would think that by now in 2016, placing a simple ProRes file in a timeline without effects, would play back real time like that in Premiere. Imagine how much more efficient a compositor's workflow would be if you could manage simple playback of untouched video clips for timing and editing prior to effects? Why should I have to "render" a clip with no effects? Makes no sense but I do understand the architecture would probably have to be altered somehow for this. My guess is they want to keep that boundary between Premiere and AE.
It's an issue when Adobe suggests that the new release is able to do so, but then it's not really meeting the created expectations.
For reference, see the latest blog post here: After Effects CC 2015.3 in depth: Enhanced Playback and Performance Improvements | Creative Cloud blog by Adobe
«After Effects CC 2015.3 (13.8) uses new playback architecture to deliver real-time playback of cached frames with synced audio. The new architecture is shared with other Adobe applications, like Premiere Pro and Audition.»
Adobe is not trying to maintain a boundary between Premiere and AE - they are working hard to give more capabilities to both apps. If you have never written even a simple app or tried to do some basic coding you have no idea how much work is involved in the process of developing software. Microsoft had tens of thousands of folks working on Windows Vista for years and look at what a mess that was.
Cut the Adobe some slack but hold their feet to the fire when you find bugs by delivering detailed bug reports. There are so many different combinations of hardware, drivers and operating systems out there it is amazing to me that a large percentage of users don't have bigger problems. I've been at the digital production game since 1997 when I adapted my Trash 80 - 2 8" floppies one for the OS and one for your data, to drive a motorized animation camera down a 6" aluminum I-beam to do repeatable moves and it's amazing to me that any of this works.