Firefox Community Forum

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.

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 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.

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

Hi, after update 137.0.1 (64-bit) using Firefox with latest Gecko driver 0.36.0 in Python Selenium stalls and fails to initiate drivers without returning initiation errors every second launch, previously this stall without returning initiation errors would happen every ~25th launch. Also when it does successfully launches previously 9 instances used to use about 95% of my 8 GB RAM, now 6 instances use 100% RAM. Nothing else in my system changed besides Firefox update.

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

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.

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'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!

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.

Firefox prompted me that my local storage space was insufficient. When I opened the data management page, I found that a particular website's local storage was abnormally large, and some websites were inaccessible or unable to log in. After restarting Firefox, the issue did not reoccur.