I installed Slackware 14.2 about a year ago, and never updated anything. I was using Firefox 50 (?) and while there were always a very few web pages that didn't display properly, I got by. Then one of my favorite sites refused to display anything, and it seemed to get worse during the next week. I went to Mozilla and downloaded the latest and greatest, which wouldn't play any audio without pulse audio, which I'd disabled.
So, I put a fresh install of Slack 14.2 on an unused partition and installed all the updates and left pulse audio enabled. Firefox is now at 52.3.0 and tons of pages and videos don't display properly, hell, even YouTube is now full of videos that only show a message "This video format is not supported by your browser". Also, it's slower than molasses in January. I googled, which pretty much suggested to disable all add-ons, but that didn't work either.
A few weeks ago I mentioned that loading "Thread locks too soon" took 10 seconds or so to load and I was thinking the browser locked up, but now the little spinning arc thing that indicates load in progress keeps spinning, but it takes even longer to load that thread.
I'm assuming my old Athlon64 dual core just isn't up to the task anymore, but jeez, really, what the hell are they thinking throwing in all this useless bloat and for what?