So I embarked upon the journey of applying refactor > move on a member variable.
The member variable has one getter, and that getter has only one caller in another class.
AppCode worked on this refactoring project for 14 minutes.
During that entire time, CPU usage was at 150% and the entire UI was locked up.
After the 14 minutes finished, I saw that AppCode moved the member variable and its getter to another class, but it did not even refactor the caller from the other class!!
Granted, the project I am working on uses a library that is somewhat large, and I've been told that this can cause AppCode to work slowly. That really isn't an acceptable excuse though since XCode works just fine with this library, speed-wise. That said, I don't think it's fair to charge this much money for a product that is this slow. Even simpler things like AutoComplete are so slow (takes 8-15 seconds to activate) that I type everything out myself.
I've done all the regular steps of increasing memory usage, and all the other suggestions their (genuinely friendly) customer support staff have suggested. The project is in C++ and I'm using AppCode 2018.3.