My daily-driver linux UI (fvwm something or other, whatever the fvwm that comes with Debian 10) is noticeably slower than my daily-driver linux UI as per 1997-2

My daily-driver linux UI (fvwm something or other, whatever the fvwm that comes with Debian 10) is noticeably slower than my daily-driver linux UI as per 1997-2002 (gwm). Which is somewhat ironic, as gwm was basically an interpreter with a bunch of built-in X11 manipulation primitives. But, back then, getting the "desktop context menu" up too approximately no perceivable time, whereas these days I notice time passing. I don't think that is because my reflexes have improved massively in the last 20 years.