Premiere/Media Encoder Eating Up Memory

After years of decent performance of Adobe PR on my HPZ440, memory suddenly became an issue when I upgraded to V 12.0.  The playhead stuttered, and Memory spiked to 89% (as per Task Manager) whenever PR was running, even if doing nothing. OI played around with many fixes, nothing helped. Then, I ran the Windows Memory Diagnostic - which really isn't supposed to fix anything - and my problems instantly went away!  Memory is at 13% when PR is dormant, 28% when running a sequence with mattes, adjustment layers, lots of complexity.  CPU numbers have jumped to the 70% area, but everything works so much better, I have no idea why.  Here are the instructions I followed:

How to detect bad RAM with the Windows Memory Diagnostic tool - TechRepublic

1. Open the Control Panel
2. Click Administrative Tools
3. Click Windows Memory Diagnostic. [You can also launch the tool by entering "mdsched" in the search bar.]
4. Select "Restart now and check for problems" or "Check for problems the next time I start my computer" [If you opt to restart and run the tool now, just be sure to save your work and close any open programs for before doing so.]
5. Select your memory test options and run the test [Once the machine restarts, the tool will launch and run the memory test. You can press F1 to change the test options or just let it run with the standard settings.]
6. Let the test run [The test could take a few minutes.]

If anyone else has any idea as to why this is happening I would love to hear your thoughts. I still have not been able to solve the issue. My internal hard-drive (not my RAM) drains every time I use Premiere and Encoder, even when I have everything set to an external drive.  

RAM use goes up when the program is using the CPU/RAM system for work. The cache files and media files are not part of what's in RAM. An NLE is a very complex program, and most heavy editors will run 64GB or more in their editing rig. I've only got 32Gb of RAM in mine. And PrPro uses most of it when working.

Neil