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Firefox huge memory consumption - who's lying ?

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  • 2 have this problem
  • Last reply by webdev1

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I try to keep always open some tabs in Firefox,, probably already too many (it's not unusual to have 25-30 tabs opened, each having it's internet page). I'm using Firefox up-to-date on Windows 10 Home already at version 20H2.

So, quite quickly Task Manager comes to report that Firefox takes 1400-1600 of RAM (out of the laptop's total of 6 GB). At the same time, Firefox's internal Task manager pretends that memory taken by all tabs does not sum up more than cca 650 MB !!! This is concur with about:memory tab if I try that too.

Here's a capture taken with Snip&Sketch having both Firefox's tab with it's internal task manager, + Windows's Task manager over it (attached).

I feel like I'm cheated here, but ... who is most closer lay blame on ? Who is more likely to lie in this case ?0 Firefox or Task Manager ?

I tend to believe it's Firefox, but I'm willing to have other opinions. Are there extra memory taken by Firefox that is not reported in the about:memory tab, or in it's internal task manager ? (I'm onto this, I believe that there is something that is not reported, but so far have not a shred of evidence on this).

This is exactly why on my computer at work (on an OpenSUSE install) I gave up on Firefox and turned to Chrome, because on this one I can trust the internal task manager, and it does not crush my Linux box like Firefox eventually have done with it's crazy memory consumption and/or CPU huge load from time to time. I am still using Firefox on the home Windows 10 laptop because I share it with my wife, and decided she is to use Chrome, and myself Firefox:-)

Attached screenshots

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MemTest LAST UPDATED : 12/04/2020 Could you please run a tool from in order to check the integrity of your RAM?

You will need a thumb or disk drive to install it on.

Do you let Windows handle the page file or did you set a fixed size ? If you use a fixed size for the page file then try the former and let Windows handle the page file. How to determine the appropriate page file size for 64-bit versions of Windows {web link}

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Thanks, but all those knowledge tips were only small tips to ease the pain of using Firefox, not any real solve of my problem with it :-) I *do* restart Firefox relatively regularly (2-3 times a day), just for the purpose of one of those tips on the knowledge page for "large memory" ( ).

I would've like, though, some real insides on how to change deep Firefox settings that could make it a more civilized (decent) piece of software, considering it is really the most used software in my computer, by far.

For instance (I know this is not Firefox's fault, at least not entirely, but I am sure it's somehow about the extension mechanism to blame in part for this) - I removed AdBlock Plus and installed, instead, uBlock because AdBlock came to gulp about 500 MB for itself which is insane already. Again, I'm convinced this is not only AdBlock's fault, but also Firefox for the wrong mechanism of inserting and using an extension.

I would've like someone from the devs to assume/acknowledge this behavior and try to give some hope it will be solved in some future; I guess I'm only dreaming for a decent Firefox, anyway ... Yeah, why made a decent software, when RAM is so low at costs, so if you already have a > 8 GB RAM on your computer, they need to be used by Firefox, what are that RAM there for, right ?

For instance, this morning, immediately after starting Firefox, without even clicking on all those tabs saved in at closing time last night (saved session), I already see task manager counting 900 MB of the RAM for Firefox, with only this tab where I write this answer, plus 4 other tabs (Spotify web player, homepage and 3 other tabs -- the rest of the about 20 other tabs are not really re-opened by clicking on them). This is not only insane, but clearly insulting for me as a user !

It doesn't really mater, I don't expect Firefox will ever become a decent browser like it was 10 years ago, so my expectations are very low anyway.

P.S. Sorry I don't see an option to correct the title.

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Yeah, that you're right is sad. I've got 60 Gigs of RAM, and it's obviously not even enough, because even after rebooting, and deleting cache, I'll find everything slow down, page loading, and the worst, not being able to type without having to wait for the words to show up! Last time I rebooted, it was using 22 GIGS of RAM!! That's absurd, yet I have to laugh when I look at Firefox's Task Manager, for it's showing even the worst site is using only 250MB of Ram & is a 'low energy" consumer! Yet my Apple Activity Monitor shows it using 1.25 GBs of RAM, quite a difference, and more likely why I can barely type anything on that page...

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Suggestion: For now, create messages in a text editor. Then copy/paste to the browser.

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I am done with Firefox. Tired of the piggish memory use, and tired of never any solutions. The problem is obviously in Firefox. Today when other programs stopped working a quick look at memory and there it was at the top of usage. And it keeps climbing even if the tabs are idle. So I'm done, as soon as I transfer my favorites (the only reason I kept fire fox) I'm removing it from all of my PCs. Great job Mozilla, too bad you haven't listened regarding this issue. It's been years and nothing from you or any attempts to fix this.

Instead there are the "tips", really? So place the burden of working around a bug onto the end-user? If the effort spent on creating and disbursing those tips was spent on this glaring bug then maybe it would be fixed.

And yes, I've tried all of the "fixes". None work, no change. And yes, I leave a browser open for long periods of time, and with many tabs open, and more than one instance of the browser.... So if I can't use a tool in the way I work and do my job I will discard it and find something better.