I have Kubuntu 20.04 installed on an older Dell Optiplex 990, I7, 512 SSD, and 16 GB RAM. The installation was screaming for months and has suddenly slowed down considerably. The system monitor program shows little use of RAM but almost 100% CPU on all cores.
I am relatively new to Linux and chose Kubuntu because of the KDE Plasma desktop. I have it running also on Lenovo T440, no problems.
I would like to reinstall Kubuntu or go to OpenSuse version.
I would like to leave my data on the current drive and install the new OS on a new SSD.
What do you recommend?