Very Slow new iMac (Retina 5K, 2019) 3.6 GHz 8-Core Intel Core i9, 64G RAM, Radeon Pro 8 GB, 2T SSD
The whole system is laggy!
The UI of the macOS Catalina 10.15.1 is not very responsive. In fact, while typing this post, I encountered several lagged key when I tried to go back and modify some wordings. A click might take a second to respond, or say less than a second but it is annoying.
Typing in safari search bar is the worst. After the first key stroke, the first character shows up a least a solid second later! Other visual items, icons in dock, windows, are also laggy. A mouse drag on a window would move a while later!
It is worse than my old MBP running macOS Mojave. I migrated the whole system in my new iMac using Carbon Copy Cloner. And while reading issues from others in the forum, I downloaded and ran EtreCheck without anything helpful.