*** current problem ***
After Effects CC 2018 won't use all allocated RAM on my computer anymore and I don't know why. I have 26 GB allocated, but it won't use more than 10 (details in next section). I'm trying to render output for a part of the project, but it's going insanely slow and it's not allowing me to work on other parts (because AE/PP are tied up rendering this one).
*** background story ***
I've put a few dozen hours into an After Effects CC2018 project including 3D layers and effects. During the beginning of this project, IMPORTANT NOTE: At this point, AE had no problems using the full 26 GB of RAM (out of 32 total) that I had allocated to it.
Somewhere along the way, I ran into an issue where AE wouldn't stop crashing while rendering the preview. I tried a bunch of things including reducing the rendering quality, clearing memory cache, and also making compromises in the project itself by rearranging layers and removing 3D layers. These helped but didn't resolve (i.e. I could work a bit longer until the program crashed again).
I eventually tried uninstalling and reinstalling AE and Premiere Pro, thinking maybe something happened with the installs. I removed preferences as well. This also didn't completely fix the issue, but did seem to help.
I did more changes including resizing the page file on my system and increasing the allocated disk cache to AE. I eventually got the project into a complete-enough state to be done with it. Trying to export this project, i haven't seen AE use more than 10 GB (Premiere Pro is using 2.5, so still well under cap). The rendering time just keeps increasing. I've left it rendering overnight while it was reporting 5 hours remaining, came back 13 hours later to see it reporting 49 hours remaining. The percentage completed did increase, but minimally (i don't remember exactly how much, less than 10%).
*** some current specs, I'm not sure what's relevant here ***
OS: Win 10 Enterprise 64-bit
Processor: Intel Xeon E5-1620 3.50 GHz
Installed RAM: 32 GB
Allocated RAM to Adobe suite: 26 GB
Allocated disk cache to AE: ~30 GB
Windows page file size: 20 GB
Source media: 5400 x 2700 resolution, 1 minute long
Output settings: 4096 x 2048, H.264, 15 mbps, 29.97 fps
Current behavior (during project file export) -
AE RAM usage stays between 5 and 10 GB
PP RAM usage stays right around 2.5 GB
total RAM usage on the machine is 45-50%, only Adobe product running is Premiere Pro, and it's only rendering the AE file to the output settings above
total CPU usage is 15-25%, AE spikes it to 99% every 30 seconds or so, then returns to normal
What do I do to get AE to use all allocated RAM again?