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Firefox inputs unusably laggy within a couple weeks after every restart

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One or more form(s) of such lagginess have been occurring for me for at least a year, such that I have to restart Firefox every couple weeks to avoid the frustration.

The lags seem to apply to all of my inputs. For example, when switching tabs, typing in the URL bar or text boxes, or clicking a link. Lag time increases maybe linearly since the last Firefox restart. Within 2 weeks after the last restart, it can easily reach 2 seconds of lag on every input.

Fairly certain the lagginess always corresponds with high "memory pressure" (red/yellow in macOS Activity Monitor's RAM graph). I have 16 GB RAM. At least this most recent time, I noticed kernel_task's real memory usage was 5 GB, but its regular memory was only at ~0.5 GB. Firefox's regular memory usage was at 12 GB, real memory usage was maybe 5 GB. Firefox's "Minimize memory usage" lowered Firefox's regular memory, but not kernel_task's. And in general, I believe "Minimize memory usage" has never helped with the lag (always needs a Firefox restart).

Here is a Firefox memory report from last time the lagginess happened: https://file.io/adNYhkzolQOj

I do usually have hundreds of tabs. This lagginess was never a problem on an Ubuntu desktop I used with a very similar setup (add-ons, preferences, websites), but that desktop had far more RAM. Is hundreds of open tabs always going to cause trouble eventually given 16 GB RAM due to inescapable memory leaks that Firefox cannot free?

about:performance has never shown anything that looked odd to me. I think it never looks massively different than it does as I write this for example (shortly after a restart), where the highest-memory entries are Add-ons Manager and Task Manager at ~200 MB, followed by individual tabs with a max of 40 MB but mostly far lower. It's possible a couple extensions (especially Tree Style Tab I think?) reach higher memory over time, but I'm fairly certain they're always under say 1 GB.


I've cleared cookies & cache many times. I'd rather not remove extensions because I find so many of them so immensely useful, and the lagginess takes a long time to show up. I've already tried disabling all extensions I rarely use. I've customized about:config and my extensions a decent amount, so I don't really want to Refresh, but maybe I should?

Thanks a ton for any help.

One or more form(s) of such lagginess have been occurring for me for at least a year, such that I have to restart Firefox every couple weeks to avoid the frustration. The lags seem to apply to all of my inputs. For example, when switching tabs, typing in the URL bar or text boxes, or clicking a link. Lag time increases maybe linearly since the last Firefox restart. Within 2 weeks after the last restart, it can easily reach 2 seconds of lag on every input. Fairly certain the lagginess always corresponds with high "memory pressure" (red/yellow in macOS Activity Monitor's RAM graph). I have 16 GB RAM. At least this most recent time, I noticed kernel_task's real memory usage was 5 GB, but its regular memory was only at ~0.5 GB. Firefox's regular memory usage was at 12 GB, real memory usage was maybe 5 GB. Firefox's "Minimize memory usage" lowered Firefox's regular memory, but not kernel_task's. And in general, I believe "Minimize memory usage" has never helped with the lag (always needs a Firefox restart). Here is a Firefox memory report from last time the lagginess happened: https://file.io/adNYhkzolQOj I do usually have hundreds of tabs. This lagginess was never a problem on an Ubuntu desktop I used with a very similar setup (add-ons, preferences, websites), but that desktop had far more RAM. Is hundreds of open tabs always going to cause trouble eventually given 16 GB RAM due to inescapable memory leaks that Firefox cannot free? about:performance has never shown anything that looked odd to me. I think it never looks massively different than it does as I write this for example (shortly after a restart), where the highest-memory entries are Add-ons Manager and Task Manager at ~200 MB, followed by individual tabs with a max of 40 MB but mostly far lower. It's possible a couple extensions (especially Tree Style Tab I think?) reach higher memory over time, but I'm fairly certain they're always under say 1 GB. I've cleared cookies & cache many times. I'd rather not remove extensions because I find so many of them so immensely useful, and the lagginess takes a long time to show up. I've already tried disabling all extensions I rarely use. I've customized about:config and my extensions a decent amount, so I don't really want to Refresh, but maybe I should? Thanks a ton for any help.