AE CC (v12.2) doesn't use all 128GB of available system RAM on Win 7 x64 system,
It's not using it because it doesn't need to use it.
The bottleneck in your setup is most likely the processor. Only some things in AE are multicore or multithreaded, so you're often going to be waiting on a single 2.00 Ghz processor to crunch through a bunch of stuff and the computer doesn't need that RAM for what it's doing.
Now, that's not to say that we can't help you make it go faster. Can you upload a screenshot of your memory and multiprocessing settings?
You very multiprocessor and memory settings based on the project? I would never consider that unless there was some very specific unusual project I was doing.
Think about this for a moment. You have 12 layers in the 4K project you are working on. How much memory does it take to hold that many pixels? And very simplified terms, that's as much physical memory has that particular frame in aftereffects needs to access. The process of making the calculations to add subtract multiply or divide the pixel values of those 12 layers is then handled by the processor. Throw in a few extra bites here and the for things like blur vectors and particle generators, and you are still miles away from hundred and 128 GB.
As the others said - AE uses what it needs, not more. Your machine is hopelessly over-specced for AE work and even if you use 3D programs, the only thing coming close to using all 128 GB will be complex particle simulations with literally billions of particles.
To clarify I have 2 (two) CPUs installed, not 1 (one).
No need to clarify, we read that, but if a process isn't multiprocessor aware, it doesn't matter how many you have; it is still only going to use one. (And only one core of it too.) For some things, having two processors with multiple cores is going to help a lot, but for other things, you're going to wish you had a higher clock speed instead of multiple processors.
Have you never run into artifacting issues when "Render Multiple Frames Simultaneously" is turned on? I've run into that quite a bit (especially when using the 3D camera tracker). I purge my cache and turn that option off and many of my RAM preview artifacting or other problems disappear. So that is why I vary my settings from project to project.
Basically what I'm gathering from everyone (thanks to everyone for your help!~), is that my CPU is the bottleneck and is limiting the amount of RAM that my computer can use and in turn what AE can use. I was restricted to this CPU at the time for bugetary reasons, but this helps build my case for a beefier build.
What recommendations do you have for what the ultimate AE computer CPU/GPU build would be? I really want a configuration that can take advantage of all 128 GB of ram (especially in AE), but if that is just an impossibility for now... I'm interested in learning what the absolute best set-up on can get at this point?
Truth be told, I'm testing a HP z820 to see if this is a better option than getting a maxed out 2014 MacPro. I'd be interested in everyones thoughts on this as well. Thanks!
You should not have MP turned on for 3D tracking or for any operation that is not MP compatible, and that includes many if not most 3rd party plugins. In my normal production workflow it is almost never on because AE does not utilize it well enough yet. It does work amazingly well for a few tasks. Hopefully more will be added to the list soon.