Why IntelliJ is so slow?

I'm getting really upset on myself because of upgrading from 2018 version to 2020. 

Running a single test takes ages. It constantly parsing, indexing (or updating indexes), writing classes (that's what I see in the bottom bar) over and over again. Sometimes it complains on the compilation errors from modules that are built after the module I'm trying to test. It's so annoying I need to wait a minute before it actually starts my test. 

I was using ubuntu with my dell xps - struggling with such issues and now I'm on brand new macbook pro (64GB of RAM) and I can't see any difference. Intellij 2018 normally runs my tests quickly, overall experience was really good, it was responsive doing requested tasks almost instantly. That's not happening anymore. What's happened? Is that just happened or happening me only?