When I started working on my first project using MEP 2020 Plus, I was having constant freezes in the program while trying to move Objects. (Would hang with the cursor showing the finger-thumb grab icon.) And this was for a relatively simple project, only about 8 minutes long. At only 1080p. (Although wit a few nested animated titles.))
Since then, I've settled on using proxy files and the "Reduce resolution for improved performance" option. (Although, wow, those proxy files take a long time to build. And they're HUGE. It appears that MEP is creating uncompressed AVI like proxies.)
Also, I disabled the "Overload Optimization" setting.
No crashes since.
This is with no Blue Lightning bolt symbol in the Display Monitor. (Although I am using a window that's only about 800x600. And on the monitor driven by the UHD exclusively.)
Am still trying to figure out what "Load Images in background" does. Although it just hit me that the box to the left is titled "Video Playback," whereas the box surrounding this option is titled "Image Playback." So is this slide show/.jpg/.png specific then?