2. Please test the project in both 2017 (CC 14) and 2018 (CC 15) and clear the cache right before previewing. Look at the info panel an note preview performance.
I have a previewing performance drop of over 30x going to AE 2018 (CC 15) version compared to AE 2017 (CC 14). This applies to at least two different computers one (W10, 32GB RAM, GeForce GTX 960) the other (W7, 24 BG, GeFroce GTX 1080)
The comp should run at nearly 25-30 fps on my computers, NOT sub 1 fps.
The comp is setup with the expressions made to simulate a slot game, it's very dynamic and I can easily move around and change some simple key frames and their values and they the comp will automatically update the "game".
I need the code for the "game" to reside in the text layer, and that will produce an array (text string) containing position and timeremap data for all other participating "symbol" layers. They, the symbols, in turn parse the text layer array data to extract their individual positions.
At the moment I've moved back to AE 2017 as my livelihood very much depend on this workflow and currently 2018 (CC 15) is completely UNUSABLE, now it literately takes forever to preview anything. I'm very afraid that future versions of After Effects will continue having this poor expressions performance and I don't know any feasible workaround.
I am getting the same issue! I am in AE 2020 currently and any projects where I heavily utalize expressions puts preview and render times in the toilet. I have been looking everywhere for a soloution ... and it keeps looking like it is after effects itself. This machine has never had any issues handling heavy performance loads until I encountered this issue. Any suggestions or thoughts would be much appriciated .
Sadly I don't have an answer, but I am having the same problem so I'm going to follow this thread in hopes of an answer. Over the past coule of years I've really fallen in love with using expressions for text animation, but the slow down I'm experiencing is making it practically impossible. I'm running AE 2020 on a Mac Pro 2010, 2 x 2.93 GHz 6-Core Intel Xeon, with 64GB RAM and a Radeon RX 580 8192 MB gfx card, and I'm runing Mac OS High Sierra 10.13.6. Big thanks to anyone who might be able to help!