Purge All Drawings and xRefs

The solution for drawings that are very slow and/or become very large (10+ MB) is to purge the drawings.

Ways to accomplish this:

You can manually open each file and run the command UPU

Install this add-on:

https://apps.autodesk.com/ACD/en/Detail/Index?id=3773138176974634673&appLang=en&os=Win32_64

And then use the Batch Purge function, you can then do entire folders at once.