Does anyone have this issue were firefox becomes slow if left open for a long time. In my case after a couple of weeks rendering becomes slow and when I use youtube for example if is laggy, just trying to change volume taka few second to show the volume bar. It also happens to my laptop at work. I have around 30 tabs open.
Dawg I had like ~35 tabs open and hadn’t restarted my PC in over three weeks. Fucking Firefox was sucking back 80 gigs of RAM. 80 fucking gigs.
On the bright side all the tabs were still loaded when I clicked through them.
I’ve seen poorly made websites taking gigabytes of RAM before. It’s not firefox’ fault they do that.
True that, I just thought it was crazy. I had recently upgraded to 96 gigs of RAM and I just never imagined a browser would actually suck up that much.
If you had 80GB worth of websites that did something actually useful with it, you’d want Firefox to use it all.
I usually have dozens of tabs loaded due to usage and I want Firefox to keep all of them into memory so that I can switch between them quicker.
Though I do also want Firefox to shed load by unloading some of them whe I need memory for something else. There just simply isn’t a mechanism in Linux to do that AFAIK; Firefox will happily keep all of its tabs loaded all the way until OOM eventhough it could shed most of them with little impact on user experience. There isn’t a way for the kernel to ask applications to shed memory load on their own and I think there should be.
macOS has such a mechanism and Firefox uses it but it didn’t have much effect IME, so it might have been bugged. That was a good while ago that I tested it though.
I can’t wait for Servo to be finished so I can move away from Firefox, it uses way too much memory.
I’m so hyped as well! Just read their monthly update blog today actually! I’m mostly hyped because it’s the first actual new web browser in a very, very long time, and that’s just plain exciting!
There are two new browsers coming Servo written in Rust and Ladybird (web browser) written in Swift. Lets see which one will win. Ladybird alpha is coming in 2026 and they have more funding.
Servo won’t protect you against shitty websites gobbling up memory.
It will still lower memory usage considerably, Firefox uses way more memory than Chrome. Memory optimization is horrible in Firefox.
[citation needed]
I test firefox vs edge in my pc, both with ublock origin. Firefox noticeably uses more ram than edge which uses same engine as chrome.
Here this person saw the same results as me: https://libreddit.bus-hit.me/r/firefox/comments/18gp19l/ram_usage_in_firefox_vs_edge
Their methodology (and therefore likely yours aswell) is flawed and it was immediately pointed out in that thread too: https://libreddit.bus-hit.me/r/firefox/comments/18gp19l/ram_usage_in_firefox_vs_edge/kd2u2pq/?context=3#kd2u2pq
Measuring the memory “a process” actually “uses” is not trivial.
https://addons.mozilla.org/firefox/addon/auto-tab-discard/
I’ve got more than 30 open tabs, though in practice I don’t actually need ALL those tabs loaded. The extension unloads inactive tabs after a configurable time. You can also configure the extension so that pinned tabs are not unloaded, certain domains/URL patterns are not unloaded, etc.
Firefox can automatically discard tabs when available memory gets too short. You need to configure it to do that though and probably disable the 10min minimum open time too if you’re very short on memory.
FFS, his leak is probably in an extension.
Installing more extensions that might also leak is not a real solution, no matter what they do.
Are we all going to ignore this person had Firefox open for weeks?
Yes.
Stop trying to shame people for using their damn computer.
Stop downvoting people who treat computers the way they ought to work! Needing to restart shit, with any regularity, is a flaw. Some of us are doing work, god dammit, and having to get things set up from scratch is a pain in the ass.
All the stuff I have open is open for a reason. The fact it all gradually stops working is not excused by the fact it can be unfucked by a hard reset. It’s supposed to keep working.
Seems like a waste of electricity to me
I’m pretty sure sleep more uses more energy than turning the machine off when it’s not in use
Why is that unusual? The only time I close apps is when I restart for an update like once or twice a month.
And your computer is running THE WHOLE TIME?
Close everything and start fresh
Your productivity shouldn’t rely on keeping one piece of software running for long periods of time.
which OS do you have? maybe parts of firefox have been moved to swap or compressed memory
Windows 11.
Yes it happens. As others have said: just restart.
What might not be as clear: when you restart, if it doesn’t just come up and offer to restore your session, you can go to History and Restore Previous Session. This reopens all your tabs (actually, they won’t fully reload until you view them).
Or just use bookmarks like a normal person
they have an entirely different use case
Bookmarks are for really important stuff. Open tabs are for stuff I want to be able to easily stumble back upon, but I won’t be butthurt if I dont.
There’s nothing wrong with having more than one way to categorize stuff.
Edit: and considering that session data is also written to disk, there really isn’t much difference between bookmarks and open tabs anyway.
There is, when your way consumes resources absurdly.
It doesn’t. When you reset it, they take very little resources until you actually load them.
I had the same problem recently. Especially the youtube UI became very unresponsive and would take several seconds to respond. I have 96G ram…
I downloaded ESR instead. So far so good.
I’ve had this for years, I just exit and restart.
Try using a tab suspend extension, something like ‘auto tab discard’. Firefox has one built-in, but it’s not aggressive enough.
If it’s related to the thread you posted then try Nightly?
That’s only in Nightly right now, unfortunately; it won’t make it out to Release until v134.
Also, can I ask why you’d leave your browser open for weeks? Just curious of the use case. The thread mentions having 5700-7000 open tabs, and I can’t fathom why someone would do that. It’s not like the websites disappear if you close the tab. Nothing to do with the problem though, you don’t have to answer.
I only have around 30 open and I don’t turn off the laptop, after a while firefox becomes sluggish and I have to restart it.
Have you tested with specific websites? Could it be a tab has some have JavaScript running constantly that’s causing the issue?
I haven’t tested it at my home laptops, but my work laptop all tabs become slow. I have to restart it every time.
You should try that nightly build for troubleshooting purposes
Also, because it forces you to restart the browser every night.
Also, can I ask why you’d leave your browser open for weeks?
This just begs the question, Why do you not leave it open?
Maybe because the software is designed to make that very practical and smooth. You also might point to hardware limitations, should you have a machine that doesn’t have a lot of RAM, or perhaps you might point to simplicity, and that you don’t want to have a cluttered taskbar.
But it’s kind of ironic that you would ask why not leave software open on a post where the problem was specifically mentioned as one that is solved by closing the software.
So perhaps another anecdote is in order. I currently running three instances of Firefox (different profiles) on a low-end Celeron laptop. I don’t usually shut them except sometimes by mistake. What I do do is close tabs, if only for simplicity’s sake (because idle tabs are unloaded from memory anyway). I’m experiencing no sluggishness issues.
To conserve resources / power? Like when I’m done using an app, I close it. When I’m done reading a website or using online banking, I close it. I don’t leave my email, games or music open after I’m doing using them either. I actually turn off / sleep my entire device when I’m done using it, but that’s not what my curiosity is about.
Sure. Personally I just close the tabs, tho.
some people use tabs as bookmarks 🤷

Only the part with youtube. Don’t know if they are pulling some tricks on uBlock users, but about 10 tabs of youtube can get nasty, even with a somewhat recent workstation.
This thread is full of maniacs. Anyone who keeps more than like 10 tabs needs to do some sand art or some shit. You gotta let some things go man.
As a therapy? To learn to let go of stuff?
I don’t believe any of them. Sounds like they just want to feign outrage to seem interesting.
just close it
You can see the worst offenders in firefox by using the hamburger menu then more tools and Task manager. You can sort by ram. YouTube likes to hold gigs of ram for some videos. Close the biggest offenders and you’ll get back close to normal speed.
Ding ding ding, the only good reply in this thread.
The symptoms described by OP smell like good old memory exhaustion.













