For me, Firefox slows down dramatically as it uses more memory (e.g. more tabs and windows opened), and reaches a less-than-usable state well before it has exhausted the available memory. Tab discarding - automatic or by literally closing the tabs - does seem to recover the memory used, but does not recover much of the performance (if any). My AMD 5800 and tens of gigs of memory runs into the same crushing performance blockers as my old 8GB FX-8300 machine, with virtually the same "workload" and usage profile.
Kinda the opposite of what I'd want; I usually have over 16GB more that Firefox could use if it needed, and that's once it has reached critical mass with maybe hundreds of tabs.
Its memory measurements usually look sane, so I feel like there's some data structure or algorithm that is doing something insane in the background - which is already confirmed to be the case with the History menu, particularly if you select and delete thousands of items at a time.
Kinda the opposite of what I'd want; I usually have over 16GB more that Firefox could use if it needed, and that's once it has reached critical mass with maybe hundreds of tabs.
Its memory measurements usually look sane, so I feel like there's some data structure or algorithm that is doing something insane in the background - which is already confirmed to be the case with the History menu, particularly if you select and delete thousands of items at a time.