Update one of your PCs then give the suggestions in the link below a try.
https://www.groovypost.com/howto/fix-slow-after...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.