I've pulled back on what FF can do over the last year or so and noticed others doing so to, sometimes baffled as I have been about why a version change suddenly meant a cliff edge fall in performance when the user hadn't done anything they were aware of.
I loved groups, guess what, JTH said they might be affecting performance so I got rid of them, altogether.
I renamed my folder and started again.
Guess what?
FF was slow within a day.
I also tried FF normal, same thing.
Sort yourself out, JTH.
Something I haven't tried is use my exact PA FF on my work system which has oodles of resources, but I have noticed that FF on the work system is getting refreshed often.
JTH, at what point does a moral attachment to FF become wrong?
I am not sure it is the best browser any more.
Are you *very* sure?
You are free to use any browser we offer. My choice has no effect on yours. I use Firefox daily without issue. You're free to use something else like Chrome, Opera, or Iron portably. They won't work as well as Firefox, though, as Chrome itself (on which Opera and Iron are based) is designed to be hostile to moving data between PCs.
Sometimes, the impossible can become possible, if you're awesome!