Firefox Community Forum

I’ve noticed that Firefox consumes a lot of memory, especially when I have multiple tabs open. Sometimes, it slows down my entire system, and Task Manager shows Firefox using over 1GB of RAM even with just a few tabs. Other browsers like Chrome or Edge seem to handle memory better with the same number of tabs.

I’ve tried restarting Firefox, closing unused tabs, and disabling a few extensions, but the problem keeps coming back. I even checked techsquest.com for tips, but I’m still struggling. Are there specific settings, hidden features, or optimizations I can apply to reduce Firefox’s memory usage without sacrificing performance?

Here’s what I’ve already checked:

Firefox is updated to the latest version.

No unusual extensions running (just uBlock Origin and Dark Reader).

Hardware acceleration is enabled.

Any help would be appreciated—thanks in advance!

I have a HUGE problem with Firefox memory usage. Some open instances of firefox are taking anywhere from 600mb to 2.8gb of memory. Since firefox opens MANY instances even with only ONE active window, this very quickly uses all available memory (4gb) causing a full laptop crash.

More concerning is that CLOSING the worst instance of memory usage STILL leaves the single open page/tab open, so what exactly was the memory eating instance actually doing ???

I have included a screengrab of the many remaining instances of firefox in windows task manager AFTER closing the main culprit.

I have also included a screengrab of all the adblockers I use which I believed would limit unnecessary memory usage, but does not seem to be effective.

Many Thanks

I'm tired of trying to find a solution to this problem, you're deaf!

I have been using Firefox since 2003. to avoid writing unnecessary words, I will simply state, I will leave firefox if you do not eliminate this problem:

firefox eats up all the RAM on my Mac. It is none of your business whether I open 1 tab or 10 tabs, give me the ability to limit the memory used by firefox, otherwise it eats up all the computer's memory.

All of a sudden, I get a "Not enough room to save" error message when I try to download a fill. There is plenty of room on my disk.

Also, it's not giving me the option of just opening the file.

I've been needing to use Edge to download files.

There is a similar (but not identical) topic on Mozilla Connect , and I posted there. But I did not get a response. So I am re-posting on this new topic on Mozilla Support. I have a similar problem to what was discussed on Connect. I am using Firefox 133.0.3 on Windows 10 Professional. After Firefox has been running for a while, I get a message from Windows 10 that the free space on my C:drive is low. I did a directory listing on my C-drive before and after Exiting Firefox; I saw no large files disappearing. Then I decided to do "dir c:\ /ah" to see hidden files. What I saw was that pagefile.sys decreased in size from 29,925,748,736 to 16,270,770,176. This was a decrease of 13.7 Gb. Is this normal? I have lots of windows and tabs open in Firefox. Thanks.

Hi Community,

I am writing as recently I noticed that extreme amount of data was written on my system SSD. Here we are talking about 100-200GB of data written daily. In resource monitor I found that Firefox is writing this amount of data in its Profiles folder, but only when Facebook's main page is open. I also noticed that when only the Messenger part is open the problem goes away. Currently I symlinked the Profiles folder onto one of my HDDs so the data is being written there, however I would like to know if anyone experienced the same issue and what could be the solution for this. I completely reinstalled Firefox, my installed extensions are Adblock Plus, Enhancer for youtube and Facebook Container.

About once a minute or more Firefox lag by 10-15 seconds before showing a character or characters I have typed.

It seems to be using a lot RAM. I have one window open with six tabs, including this one, and it is using nearly 8GB. There are 48 processes showing in Activity monitor.

I am using version 135 on a Mac Book Pro running MacOS 15.3 (Sequoia).

It is almost unusable.

I've noticed my GPU fan runs heavily as soon as I open Firefox, and with even just only one browser page open, it runs high speed, where it didn't use to do this. How can I get Firefox from requiring so much of my power. I don't want my electric bill higher just because of a browser. I have a decent GPU good for gaming quality that usually doesn't get clocked enough to cause the fan to turn on and run at high speed unless it's a high-graphics computer game or something. Anything I can do to make the browser demand less on my GPU?

When I open one tab on Firefox, my task manager shows multiple programs running along side it. I know some extra processes are needed but this seems like an unusual amount. I have included a screenshot of the tasks that appear. When I try to delete these, they reappear. I have tried various online solutions such as uninstalling and reinstalling, and checking various settings. It is affecting my computer's performance and I am not sure how to solve this. Thank you!

My firefox is using up too much memory, up to 60% of my laptops memory, even when I am not using youtube. and I can't figure out what is causing it to use so much. I've used minimize memory to no effect, can you figure out what is causing it? This link has a memory report to help

Has anyone else noticed that the memory leak issues have gotten way worse since last update?

I work on a potato. Most of the memory is in the windows paging file, on a mechanical hard drive. So freeing up used memory takes longer than it would on a machine with a metric tonne of quad-channel RAM. The past 6 months, Firefox has started having memory leak issues, where it just uses more & more memory until the paging file hits its hard limit and windows kills firefox.

But since last update (135.0 x64), the memory leak issue has worsened significantly.

If I open firefox, and then tab between all current tabs, I get maybe 5 GB of memory usage. So even if all tabs are marked as "active" and loaded into memory, this still isn't enough to cause issues.

But after 30 minutes, that memory usage has ballooned up to >20 GB, at which point windows decides that it needs to free up memory, and kills the process. Which is annoying, because then the browser reverts to the last saved state, meaning many tabs can be lost or reset to several clicks back.

I've tried shaving off extensions, with zero change. I've tried increasing paging file size, but that's just kicking the bucket down the road.

Anyone have a solution to this?

I am on a Mac desktop running Ventura 13.7.3 and running Firefox 135 with extension of Ghostery, Privacy Badger, Google Don't Track Me, Facebook Container, FoxClocks and SoftGreenLeaves theme. All of these extensions have been playing nicely with each other for a long time.

Recently I've been having trouble recently with Firefox doing that thing of suddenly freezing/producing multiple windows and I need to refresh in order to get it working properly again. This has happened three times in the last five days - so frequently that I now keep the refresh instructions on my desktop. Today I heard the CPU grinding and clicked open my Activity Monitor to see four listings of 'FirefoxCP Isolated Web Content' running all of them using in excess of 2Gb. Unfortunately I wasn't able to get a screenshot of the Activity Monitor while this was going on as I had the Mac force quite Firefox and the moment I did, the activity stopped, but I've attached an example of the Activity Monitor showing still high CPU values for a few moments of browsing.

So what's up? How can I stop the CPU grab? How can I stop the frequent crashing?

I am a heavy Firefox user, and have been using it (and its predecessor) since Netscape. In the last year, the size of my Firefox profile has more than doubled, from 500MB to 1.3GB. What's the probable cause(s), and what can I do about it?

Firefox is creating very high CPU use with many WebThumbnailExtension Web Connect processes. The processes disappear after shutting down Firefox and other programs that access the internet. Does anyone have an answer on how to prevent this from happening?

MacBook Pro M4 with MacOS Sequoia 15.3.1

Lately, I’ve noticed Firefox consuming more RAM, especially with multiple tabs open. Is this a common issue in recent updates? What are some tips to optimize Firefox performance on lower-end PCs? Would love to hear your experiences!

Hi, I use Firefox all the time, love it. But I have noticed a problem.

If I have say 7 tabs open, none of them doing anything, then go away from my laptop for say 20 minutes, when I come back the fans on the laptop are screaming. Even if it was minimise.

I have a fairly modern laptop Dell GSeries1522, 12th gen processor, 16gb ram, i7.

I have tested this issue using Edge and Chrome with exactly the same tabs open and the laptop is all quiet. I'm on the precipice of moving to Edge. Happy to provide more information. Task Manager now shows FF using 1223.0mb of memory, Edge 466.7mb. They are both in "efficiency mode".

Any help or advice would be great.

Peter Hall Brisbane, Australia.