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!

Hello Team,

I'm working on building Mozilla FireFox on my riscv64 development platform on Ubuntu-22.04, Below is the source and branch from where i'm using the sources.

https://github.com/mozilla-firefox/firefox.git (Branch: FIREFOX_139_0b10_RELEASE)

I'm following the below steps for build firefox:

Created a mozconfig file with the following contents:

mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/objdir mk_add_options AUTOCLOBBER=1

ac_add_options --enable-application=browser ac_add_options --disable-debug ac_add_options --enable-optimize ac_add_options --disable-tests ac_add_options --without-wasm-sandboxed-libraries

Installed dependencies:

apt-get install -y python3-dev curl curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh pip install -U pip ./mach bootstrap cargo install cbindgen apt-get install -y nodejs apt-get install -y llvm-14 llvm-dev clang libclang-dev libpango1.0-dev libx11-xcb-dev libxcomposite-dev libxdamage-dev libgtk-3-dev

Configured the build:

./mach configure

During the build, I encountered an error with Cairo version 1.16.0, so I updated Cairo to the latest version by doing the following:

tar -xvf cairo-1.18.4.tar.xz apt-get install -y meson mkdir build && cd build pip3 install --upgrade meson meson .. --prefix=/usr/local ninja sudo ninja install pkg-config --modversion cairo

After which I executed build:

./mach build

The build took ~14 hours and reached this step:

892:50.50 Compiling gkrust v0.1.0 (/root/firefox/toolkit/library/rust)

However, after about 30 hours, I ran into an Out of Memory issue. I am using a 64GB SD card for the build and have created a 10GB of swap space within the 64GB, but still encountered this error:

[189659.052881] Out of memory: Killed process 52440 (rustc) total-vm:14996824kB, anon-rss:5113116kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtab0 2811:13.62 error: could not compile gkrust (lib) 2811:14.39 Caused by: 2811:14.50 process didn't exit successfully: `/root/.rustup/toolchains/stable-riscv64gc-unknown-linux-gnu/bin/rustc --crate-name gkrust --e) 2813:03.10 gmake[4]: *** force-cargo-library-build Error 101 2813:03.15 gmake[3]: *** toolkit/library/rust/target-objects Error 2 2813:03.44 gmake[2]: *** compile Error 2 2813:03.70 gmake[1]: *** default Error 2 2813:03.90 gmake: *** [client.mk:60: build] Error 2 2813:04.19 W 271 compiler warnings present.

Could you please help me troubleshoot or suggest how to resolve the memory issue?

Any help & support is greatly appreciated!

Regards, saiteja

Have any of you noticed how much resources Firefox use? Task Manager tells me Firefox requires 11 to function using 700 megs of memory. I have 32 megs on board and if I run auto-clicker on Firefox my fan needs to run to cool the processor... This doesn't happen on Chrome. Firefox is my browser of choice... (add-ons)

I have been using Firefox for many years now and I have always been greatly satisfied with its stability, performance and features. However with the last couple of releases something has changed. The number of tabs I keep open and what they are connected to have changed very little over the years. The CPU utilization has never been much but now it has become huge - utilizing multiple CPU cores and running them at 100% whether I am using the browser or not. I have gone thru each individual tab/web page removing it, waiting for a period of time and them re-adding it assuming this was a website coding issue. Nothing changed. So I gave up and move 98% of my web browsing to another browser (Opera) - moving one website at a time until what was left on Firefox was 11 tabs. Finally the CPU utilization went away. I got the latest Firefox version update today, installed it and now Firefox has changed behavior yet again. Those same 11 tabs will not use any CPU as long as I keep Firefox open and visible on screen, but if I minimize the Firefox window it immediately jumps up in CPU utilization. This makes no sense to me.

What adds to all this frustration is I am running on a system76 Thelio desktop. While extremely fast they have a known issue with their somewhat loud CPU cooling fan kicking in too fast when high CPU utilization occurs. Firefox never used to cause the fans to run but now the latest couple of versions cause the fan to run continuously.

Here is a paste from "top" showing the top 2 cpu processes - both from Firefox and the browser is minimized:

416154 greeves   20   0 3796844 612012 260196 R 109.6   0.9 147:49.17 firefox-bin                             
416394 greeves   20   0 3537408 822456 130500 R  89.7   1.3 146:40.46 Web Content 

 My apologies if I have run on with too much info that is of no help.  If anyone has any ideas it would be appreciated and I would be happy to test.  FYI, my OS is up to date, Firefox is up to date, BIOS is up to date, I have restarted Firefox many times and I have rebooted several times.  I thought Mint might be the issue so I loaded Pop-Os and tried it with the same results.  Btw neither Opera or Brave shows the problem.  However I would prefer to use Firefox as I really like the features - especially how it handles tabs and grouping them.

Thanks in advance for any help!

Signature <unknown in nvwgf2umx.dll> | NDXGI::CDevice::FlushAndEnqueueSetEvent More Reports Search UUID d9593aae-27fc-42b4-ac33-c4df80250512 Date Processed 2025-05-12 00:33:56 UTC Uptime 603 seconds (10 minutes and 3 seconds) Install Age 169,246 seconds since version was first installed (1 day, 23 hours and 46 seconds) Install Time 2025-05-09 13:27:28 Product Firefox Release Channel release Version 138.0.1 Build ID 20250430203103 (2025-04-30) Buildhub data OS Windows 10 OS Version 10.0.19045 Windows Error Reporting

True

Build Architecture amd64 CPU Info family 6 model 23 stepping 6 CPU Count 2 Adapter Vendor ID

NVIDIA Corporation (0x10de)

Adapter Device ID

GT218 [GeForce 210] (0x0a65)

Startup Crash

False

Process Type gpu Crash Reason EXCEPTION_STACK_BUFFER_OVERRUN / FAST_FAIL_STACK_COOKIE_CHECK_FAILURE Crash Address 0x00007ffe333bfbf0 Total Virtual Memory 140,737,488,224,256 bytes (140.74 TB) Available Virtual Memory 138,531,054,325,760 bytes (138.53 TB) Available Page File 1,231,540,224 bytes (1.23 GB) Available Physical Memory 747,290,624 bytes (747.29 MB) System Memory Use Percentage 76 EMCheckCompatibility

True

App Notes

FP(D10-L1000-W0000100-T01) DWrite? DWrite+ WR? WR+The Crash report shows thus and my pc lost power suddenly and could not continue browsing .

When opening Firefox, Duplicates open but are unseen. I may have 2 tabs open but my task manager tells me there are 14, sometimes 31. What can I do to stop or get rid of the duplicates pages. if I can't I will have to remove Firefox.

firefox 138.0.1 is eating up memory, specifically;

-contentproc -isforbrowser -prefshandle

theres over 20 of them requiring 200mb each

please tell me how to turn this off

thx

Firefox consuming too much Memory, ranging from 1800 MB up to 2000 MB, causing my other programs (most notably Corel WordPerfect) to constantly crash. How do we resolve this?

Hi,

there are massive performance issues while playing videos on Youtube while using Firefox. This does not happen with the same video while using edge. The attached video shows the used memory and CPU of the youtube tab from the firefox process manager. This was taken after playing the video for 30s. Letting it run longer resulted in firefox taking up 20GB of RAM.

I think this happens since I installed 138.0 of firefox.

Could you please take a look.

Thanks.

Best regards

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

Hello, I am running win 7. Yes and Old computer. When the system is running slow I do a task manager to see what might be causing it.

I have noticed multiple Firefox processes running with 0 CPU usage. What are all those for and do I need them? Can I disable them?

On a separate issue I am getting this rendering error. This may be a Microsoft question, but I thought I'd ask. Error in rendering player Error Code: 400-404 Session Id: k6x4392p (Pls: 35a725dd-3aac-4813-8431-159ebc196c01)

Lastly I did contact support about uninstalling two Firefox programs. I deleted the one you said.

Thanks again for all the help, Irv

i noticed that my laptop is getting too hot, when i opened task manger i found that Firefox is using a lot of ressources every time, i have a decent ram of 24GB and i7 7th gen plus an gtx1050, i don't think it's my work flow because i've been always using too much tabs without any problem, i suspect an update issue, what do you think ?

Power consumption of Firefox is so high that it nearly killed the display of my iMac. My screen started flickering with horizontal lines across the display. When i touched the screen, it was so hot that I could boil water using it. I did not realize that it was Firefox that was killing my PC until I looked at the power consumption (see the attached screenshot). I hope there is a solution to this since I really love Firefox and have been using it for well over a decade.

One page of Firefox 115.21 opened and Task manager memory usage for Firefox reports-:

1) 9,956 K 2) 46,288 K 3) 11,564 K 4) 55,268 K 5) 21,560 K 6) 9,996 K 7) 5,516 K 8) 302,924 K 9) 40,272 K

These are ALL marked Firefox and in order on my Task Manager, the Page 'opened' was Firefox help forum ,,,, some memory usage here, is this right????

Dave

Firefox uses too much memory, with 1 tab 1GB+, and with 4 tabs all 3GB+, this is not normal, the forum topic did not help, reinstalled and did not help, there are no more than 6 extensions, and they consume only 160mb.

I have two Firefox tabs open on my browser. Task manager shows 35 tabs using 897 MB of memory. How do I make this stop? And why are so many tabs running? I have cleared cache, cookies, etc.

Is this a bug or config problem?

Occasionally, FF (Linux desktop) starts using a lot of memory. I kill tabs (sometimes it is OK to kill YouTube or X, sometimes not)

Eventually it starts impacting the system using so much memory. I terminate the FF instance. Often. More often than not. There is a separate task still running and I get the "Firefox is still running" when I try to restart. I then kill the remaining FF task via the OS or the process monitor. Then FF restarts.

Is this an issue with addons (I am running very few - uBlock Orign, and Privacy Badger and Cookie AutoDelete. Are the only ones active most of the time) Or is it an actual bug with garbage collection, and tasks getting away? Or is it an OS issue?

Firefox is running too many processes in the background. You have eliminated access to the user settings to be able to reduce that number. It is using so much memory (two tabs, one window, 1400 MB) it is becoming a nuisance rather than an asset. How do I reduce the number of processes. Thanks

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.