If you are all sure that your internet speed is good (if some sites and web pages are OK it probably is)
You could try uninstalling your web browser and re installing it. I must confess that AB is probably the worst offender in my case. I am running w10 with the Edge browser which I find great for every site except AB. I even, on occasion, if I want to post a reply and the site is busy, have to open my email drafts option and type up my script there, then copy and paste it to the AB reply box. I think that Buen is a big fan of Firefox. But I would try the re install of your current browser and see if the new download gives you a better version or irons out any glitches that may be embedded in your current version. Some people use third party ad blockers, but I would not advocate this for fear of displeasing the Ed. Plus of course AB survives on the revenue gleaned from the damned ads. Another thing to consider is your router or router set up. It may be a DNS (Domain Name System) resolution issue. I think that google chrome has an open DNS 8.8.8.8. and log all your traffic. You could try looking at your ISP(Internet Service Provider) DNS and try using them. It gets a bit techie to do these things I know. Just a question, do you find that your other sites or open tabs are quicker and OK if you are not logged into AB.