Try running the same distro on a live USB drive. If it runs faster on USB then it’s likely your HD that’s the problem. As many have said, XFCE is very light weight, if you can’t get KDE running smoothly. As an experiment you could try installing Fedora. The way the installer works is that it boots a live version, which you can use. In the live version you have an icon to install to your system. Use the live version a while, then install and run the installed version. Normally the installed version should be noticably faster.

I was one of the reiserfs users before it happened and I dumped it quickly. I think an awful lot of people did the same, and since it was one of a number of alternatives to ext I think it is more abandonment than obsolescence.

Now I think my decision was wrong headed, so long as he was no longer involved. The NASA example was given. Alfred Hitchcock movies? Abuser of women but damn good films.

In NixOS you can just mount your directories and run nixos-generate-config.