Since I installed the most recent Catalina update I’ve been having trouble accessing websites. If I choose a bookmarked site it can take from 45 seconds to more than a minute for the home page to display, and the same applies if I choose to navigate to a new page in the web site. If I restart the computer the problem goes away for a time, but then comes back pretty quickly. I’m finding that the copy of Windows 10 that I’m running using Bootcamp on an older iMac is much more responsive!
I should say that I’ve run CleanMyMac on the Catalina iMac, and that web access from my iPads is working fine.
I have also experienced this and found that a safari restart solved the issue.
Installed quitter by Marco Arment and set safari to quit after 30 minutes of inactivity.
btw: also good to check if the DNS settings on the macOS and windows 10 machines are different. Sometimes my 184.108.40.206 DNS gives me issues and I have to temporarily switch to 220.127.116.11
Restarting safari solved nothing for me, sorry to say. The router addresses on both machines are the same.
It turns out there were compatibility issues with my Intego software - specifically NetBarrier - and Catalina. Intego have produced an update which I installed. After a bit more frigging around after that the problem went away.