First of all, I've been having this problem in various forms for years. I stopped using Firefox years ago and switched to Pale Moon because of it, which was possibly a li… (read more)
First of all, I've been having this problem in various forms for years. I stopped using Firefox years ago and switched to Pale Moon because of it, which was possibly a little better, but still had issues. I now use Waterfox and Tor Browser, and both have issues as well. So it seems to be an inherent issue with the browser itself. I had issues on XP years ago, then on 7 for years, and now on 10. Both 7 & 10 were/are 64-bit for both OS and browser. I use a lot of tabs, and currently have ~120 open in Firefox; however, currently only ~40 are actually loaded, so it's really not that many, yet the problem still exists.
Basically, one of two things happens, or both: after anywhere from less than a day to several days, the browser will slow down or it will crash. When it slows down, even small things take forever. For example, hovering over a tab will take a few to several seconds for the tab to change color indicating it's being hovered over (which also means clicking on a tab to switch to it takes as long), clicking checkboxes in my email is slow and unresponsive, and typing will freeze every few to several characters. When it gets real bad, the browser will say "Not Responding" and even fade out until it comes back, doing this very, very frequently, until it eventually just crashes.
It also doesn't seem like it could be a hardware issue, considering I've experienced this across multiple computers, and I just had Waterfox slow down with the "small" number of tabs open on my current computer (64GB RAM, Samsung 960 Evo) whereas I've had 500+ tabs open on my older computer (32GB RAM, 850 Evo). In fact, when it just happened, I checked the memory usage and it was using ~10GB, with only ~42% of my total memory being used, so it's not like the system was running low causing paging (not that that should make that much difference with my drive). And Windows and all other programs are fine whenever it happens; it's always just isolated to Firefox/Waterfox/Tor/Pale Moon. I did a garbage collection and a cycle collection, neither of which changed the memory usage or made any improvement, so I then did "minimize memory usage," which may have. I say may because the memory usage is now down to 8GB and Firefox is working well again, but I'm not sure if that's what did it. I have e10s set to 7 processes, which I understand makes it use more memory (though 8-10GB seems awfully high) but, as I said, I have more than enough. It almost seems like when the browsers reach a certain memory use, which seems to vary based on the browser and has nothing to do with the amount of memory available, they start having issues. Tor Browser seems to slow down and crash around 3-3.5GB, for example.
Also, it's doubtful it's add-ons, since I've used different ones over the years and with different browsers, I have almost all disabled in Waterfox, and I'm using even less in Tor, and only NoScript is common between them. I'm convinced the core of the browser is just not coded well enough to handle more than a small handful of tabs, but I'm hopeful somebody can provide some guidance to fix the issue, because otherwise I just don't know if I can stay with *fox, as I need stability in a browser.