Please see the help article High memory usage.

Try starting Firefox in its Diagnose Firefox issues using Troubleshoot Mode (hold down the SHIFT key when starting Firefox) and see if you still have the problem after performing some normal browsing.

If the problem goes away in safe mode,

then you likely have a plug-in, add-on, or a combination of two or more that is causing the problem. Because Firefox allows users to customize endlessly, sometimes there can be conflicts between customized items, so to determine if this is the problem:

Restart Firefox normally, then disable all plug-ins and add-ons with

Tools -> Add-ons

then re-enable them one by one, restarting Firefox after each and testing after each one to see which one or combination of two or more is causing the problem.

If the problem still occurs in safe mode,

1. Create a new Firefox profile for testing (see: Managing Profiles), and don't install any add-ons in the new profile.
   
   
2. Run Firefox with the new profile (no add-ons installed and all plug-ins disabled).
   
   If the problem still occurs with a new profile, then
   
   Check for updates to your video drivers both on your operating system and on the manufacturers' sites, install any of those updates and reboot. See the help article Upgrade your graphics drivers to use hardware acceleration and WebGL
   
   If no updates or problem still occurs after updates:
   
   
   1. Download a fresh copy of Firefox from mozilla.org/firefox
      
      
   2. Re-install Firefox (see: How to install Firefox on Windows for more help. )
      
      
      1. uninstall Firefox,
      2. delete the Firefox program files folder, (important)
      3. reboot before re-installing,
      4. re-install with administrator privileges. (important)
         
   3. Run the new installation of Firefox with the new profile
      
3. Install your add-ons and re-enable your plug-ins in the new profile, one by one, testing after each for problems

If you still have a problem, please report back here with the steps you took, and with a full troubleshooting report

            (Help -> Troubleshooting information)

Please mark this issue as "Solved" if it solved your issue, or post back if it did not.

edited to detail reinstall process

I have exactly same problem. and the method described above doesn't work. My firefox is plugin-free, except for adobe player stuff. usually i have high memory usage, where high is 1GB and MORE, when i'm visiting websites with high image content (about 20 pictures in a window), such as photo-galeries. But today i've experienced a completely new, devastating memory leak. opening facebook and seeing Firefox memory usage skyrocketing from 1.7 GB to 2.5 GB in just 5 seconds, right before it crashed. Bravo firefox! i bet you got the ultimate record in that! I have printscreens of this record beating memory leak if somebody is interested in.

Reinstalling from clean did not do anything. Removing add-ons did not do anything. Even on my MacBook Air this happens (but to a much lesser extent)... Memory usage climbs slowly as I browse, then after a while it goes higher and higher and gets laggier and starts freezing...

I always update everything to the latest, I doubt it's the problem...

Read the help article. Followed every suggestion exactly. I even uninstalled and reinstalled FF8.01. Problem persists. Frankly, FF has been taking a quick trip downhill starting with Version 4. Mozilla seems to have reverted to the shoddy practices of the AOL days.

Are you using a ZoneAlarm firewall? There are many posts in the ZoneAlarm forums where people are reporting similar issues.

If using ZoneAlarm, please try the following test: in your System Config settings (on Win7)

     Start > All Programs > Administrative Tools > System Configuration

Uncheck the box for the ZoneAlarm Browser Security, restart, run Firefox with a new testing profile. See if this makes a difference and please report back your result.

edited to add: For this test you may need to disable the ZoneAlarm Toolbar in Windows Services as it will start up automatically in standard installations. There is currently a confirmed bug in ZoneAlarm free version that installs the toolbar even if the user "opts out" during installation.

Here's a tip on how to reduce memory usage when it is minimized: 1. Start up Firefox 2. Type in about:config in the address bar and hit Enter 3. Right click and choose New > Boolean 4. Type config.trim_on_minimize in the pop-up box and hit Enter 5. Select True and hit Enter. 6. Restart Firefox

I WILL DO MY BEST TO KEEP FIREFOX AWESOME!!!!!

GEIAN THE HERE :))))

HOPE IT HELPED :)

GEIAN THE HERO

Something else which the programmers should be aware of is that once exited, the program continues. It increases the memory usage by upto 150,000kb and uses about 25% CPU usage. And can take upto 10 minutes to finally exit. This is a memory leak and nothing else. Also since you can only load add-ons which work with the latest build of Firefox (8.O) this automatically cancels the idea that these are causing the problem. Since some who do not use add-ons also get the same problem, this again confirms that it is solely a Firefox programming problem and nothing else. I notice that this is a recurring problem since v4.0. I am seriously thinking of returning to v3.6 which worked perfectly. A second point the plug-in containers also slow down the machine and interfere with the workings of Firefox, I generally remove through task manager as soon as one appears solving some problems, but not all.

han91nah73:

I would like to know how it goes if you downgrade to v3.6 because I am under the impression that the older versions are not as secure. I've been running the latest version and about a month ago my PC was infected with a rootkit while Firefox was running. I also use Chrome and IE, altho FF was the only thing I was running at the time. This is the first virus I've been unable to repair working in IT for 14 years. (Altho I haven't nuked that PC yet, still hoping I can succeed at some point.) I've experienced the same memory leak problem for awhile, and I am convinced Firefox was maxing out and about to crash when the rootkit activated. I am running a different PC now, built a few months ago with the latest version of FF installed. Thanks.

• Windows 7 Ultimate 64-bit
• Firefox 8.0 (Adobe Flash only add-on)
• Microsoft Forefront Threat Management Gateway 2010 (client/domain)
• Microsoft Security Essentials

Well, I don't think Firefox would be to blame for the virus, in my experiences it's the most secure browser. For removal have you tried TDSSKiller?

Is there an extension that can track which extensions are hogging up the memory?

if there isn't Firefox should build something that shows the memory usage of themes/ extensions / plugins whatever... so users know which ones to avoid..

Tired of seeing over 1GB hogged up and browser and computer slowing down. tired of FF :(

It is normal for FF to use a lot of memory. Some of it is just plain leaks. Every time you open or close a tab or a window, FF will leak a little memory. Also, the FF memory manager has serious issues asking for memory. If the computer runs out of physical memory, the memory manager is supposed to ask the operating system for a new allocation of "paged" memory. Chrome does it quite well. I've seen 3GB memory systems running Chrome happily along using 8GB of "paged" memory (although the hard drive isn't too happy about all the thrashing LoL). But FF, on the other hand, will soon hang and die. I have a 3.5GB system and FF will typically get to around 1.4GB and start becoming non-responsive. If I do not restart the system PDQ, FF generally crashes and leaves the memory inaccessible so I have to restart the system anyhow. All versions of FF since 3.0 seem to have this condition. My guess it is something in the code at a very core level and thus unfixable. The general solution is to ... like all good little Windows users are taught from day one ... close down your computer at night, restart it in the morning, and only run one thing at a time (ie, Office ;-) LoL.

Well, yes, but they know its an issue, they're just too lazy to fix it. Even if its an issue in some core code, they're going to have to fix it sooner or later, and they should do it sooner so as to limit the amount of people switching to chrome crap...

So fed up with Firefox - ever since this dumb releases withouts testing properly, its been getting worse after version 4.

Memory hogging up 1.4 gig and it would be higher if I did not close tabs (which I actually want to keep open), slow loading pages.

It told me its version 8.0 - I uninstalled everything, deleted all the profiles, downloaded and reinstalled a new copy which says its 8.01 with the same memory problems - same sluggishness.

I was trying Firefox Sync for a couple of months - yesterday I gave up on that - Firefox Sync gets server problems, runs slowly at times and coupled with this memory leak issue it brings the whole browser to a halt.

I would use other browsers if I could but they all suck and don't do what I use Firefox for. I have done the reinstall, I have removed / disabled add-ons and still it gobbles up memory, drags to loading pages, hits the hard disk because I can hear it getting more noisy as the use memory increases.

Someone fix this sooner and don't call any new release version 9 unless its got something significantly new in it.

I even had trouble with this forum, been on here before and moaned about a few things, forgotten password, entered my email and the forum tells me email sent, waited hours on end, no email. Then I tried register and it registers me again - why does nothing work properly.

Other problems with firefox - the old problem with Flash videos (very sluggish compared to Chrome). Boomark All dialogue grows in horizontal width the more you use it. Firefox Sync makes things worse. This 8 / 8.01 has crashed so many times I have forgotten because of the memory leak.

I've got the same problem. I just tried a fresh reinstall, set Firefox 8.0.1 in Safemode, and parked on a very simple website without any dynamic content or ads. In Resource Monitor I could then watch the memory requirement for Firefox slowly increase, even though I wasn't surfing, and after about one hour when memory requirement hit 350 megs AVG started complaining that Firefox was using a lot of memory and should be shut down. Restarting Firefox brings memory usage back down to about 130 megs.

IMO it's a memory leak in 8.0.1.

(Windows 7 Ultra 64-bit, 4GB RAM, windows firewall, AVG antivirus, updated ATI video drivers via Steam. Yes, I've tried the "High Memory Usage" guide.)

EDIT: The problem still exists in the beta version of Firefox (9.0).

Firefox has a tool called about:memory to see how your memory is being allocated. You can type about:memory into your location bar and press enter. This gives you a list of what parts of Firefox are using memory (and what tabs are in particular). Do that and see where the bulk of the memory usage is and maybe we can help figure out what's wrong with your system.

'about:memory gives me the list below - that was just opening up some of the indicated web pages in the list - vBulletin web site causes much of the damage. That is with two windows of firefox with multiple tabs in each - its gobbling up 640MB and has reached 1.4GB many times.

I keep having to close tabs to do anything or wait for Firefox to crash.

Main Process

Explicit Allocations 617.18 MB (100.0%) -- explicit ├──296.10 MB (47.98%) -- js │ ├───82.05 MB (13.29%) -- compartment(http://forums.moneysavingexpert.com/foru...) │ │ ├──35.12 MB (05.69%) -- gc-heap │ │ │ ├──18.83 MB (03.05%) -- objects │ │ │ ├──10.70 MB (01.73%) -- shapes │ │ │ ├───5.01 MB (00.81%) -- arena-unused │ │ │ └───0.58 MB (00.09%) -- (3 omitted) │ │ ├──19.37 MB (03.14%) -- scripts │ │ ├──15.63 MB (02.53%) -- mjit-code │ │ ├───4.08 MB (00.66%) -- mjit-data │ │ ├───3.89 MB (00.63%) -- property-tables │ │ ├───3.11 MB (00.50%) -- object-slots │ │ └───0.86 MB (00.14%) -- (3 omitted) │ ├───36.63 MB (05.94%) -- compartment([System Principal], 0x5559000) │ │ ├──19.02 MB (03.08%) -- gc-heap │ │ │ ├──10.40 MB (01.68%) -- objects │ │ │ ├───4.98 MB (00.81%) -- shapes │ │ │ └───3.65 MB (00.59%) -- (5 omitted) │ │ ├───7.55 MB (01.22%) -- (6 omitted) │ │ ├───6.81 MB (01.10%) -- mjit-code │ │ └───3.24 MB (00.53%) -- object-slots │ ├───26.71 MB (04.33%) -- compartment(http://www.facebook.com/plugins/like.php...) │ │ ├──11.21 MB (01.82%) -- gc-heap │ │ │ ├───6.13 MB (00.99%) -- objects │ │ │ ├───3.86 MB (00.62%) -- shapes │ │ │ └───1.23 MB (00.20%) -- (4 omitted) │ │ ├───5.46 MB (00.88%) -- scripts │ │ ├───5.04 MB (00.82%) -- (6 omitted) │ │ └───5.00 MB (00.81%) -- mjit-code │ ├───22.08 MB (03.58%) -- compartment(https://plusone.google.com/_/+1/fastbutt...) │ │ ├──10.23 MB (01.66%) -- gc-heap │ │ │ ├───5.66 MB (00.92%) -- objects │ │ │ └───4.57 MB (00.74%) -- (5 omitted) │ │ ├───5.36 MB (00.87%) -- scripts │ │ ├───3.50 MB (00.57%) -- mjit-code │ │ └───2.99 MB (00.49%) -- (6 omitted) │ ├───15.79 MB (02.56%) -- compartment(https://bay164.mail.live.com/?id=64855) │ │ ├───6.44 MB (01.04%) -- gc-heap │ │ │ ├──3.48 MB (00.56%) -- objects │ │ │ └──2.96 MB (00.48%) -- (5 omitted) │ │ ├───5.27 MB (00.85%) -- (7 omitted) │ │ └───4.08 MB (00.66%) -- scripts │ ├───15.37 MB (02.49%) -- compartment(http://platform.twitter.com/widgets/hub....) │ │ ├───7.95 MB (01.29%) -- gc-heap │ │ │ ├──4.06 MB (00.66%) -- (5 omitted) │ │ │ └──3.89 MB (00.63%) -- objects │ │ └───7.41 MB (01.20%) -- (8 omitted) │ ├───15.02 MB (02.43%) -- compartment(http://uk.mg40.mail.yahoo.com/neo/launch...) │ │ ├───7.97 MB (01.29%) -- (8 omitted) │ │ └───7.05 MB (01.14%) -- gc-heap │ │ ├──3.67 MB (00.59%) -- (5 omitted) │ │ └──3.38 MB (00.55%) -- objects │ ├───13.41 MB (02.17%) -- (19 omitted) │ ├────9.77 MB (01.58%) -- compartment(https://secure.shared.live.com/_D/F$Live...) │ │ ├──6.43 MB (01.04%) -- (8 omitted) │ │ └──3.33 MB (00.54%) -- gc-heap │ │ └──3.33 MB (00.54%) -- (6 omitted) │ ├────8.71 MB (01.41%) -- gc-heap-chunk-dirty-unused │ ├────8.46 MB (01.37%) -- compartment(http://uk.yahoo.com/) │ │ ├──5.27 MB (00.85%) -- (7 omitted) │ │ └──3.19 MB (00.52%) -- mjit-code │ ├────8.34 MB (01.35%) -- compartment(http://www.bloomberg.com/) │ │ ├──4.39 MB (00.71%) -- (8 omitted) │ │ └──3.94 MB (00.64%) -- gc-heap │ │ └──3.94 MB (00.64%) -- (6 omitted) │ ├────7.12 MB (01.15%) -- compartment(http://uk.reuters.com/) │ │ └──7.12 MB (01.15%) -- (8 omitted) │ ├────6.82 MB (01.11%) -- compartment(atoms) │ │ ├──4.46 MB (00.72%) -- string-chars │ │ └──2.36 MB (00.38%) -- (1 omitted) │ ├────4.68 MB (00.76%) -- compartment(http://www.ft.com/home/uk) │ │ └──4.68 MB (00.76%) -- (9 omitted) │ ├────4.46 MB (00.72%) -- compartment(http://3cp9lcoq32dpn-c.c.yom.mail.yahoo....) │ │ └──4.46 MB (00.72%) -- (9 omitted) │ ├────3.70 MB (00.60%) -- compartment(http://www.bbc.co.uk/) │ │ └──3.70 MB (00.60%) -- (8 omitted) │ ├────3.59 MB (00.58%) -- compartment(http://36ohk6dgmcd1n-c.c.yom.mail.yahoo....) │ │ └──3.59 MB (00.58%) -- (9 omitted) │ └────3.41 MB (00.55%) -- compartment(http://www.google.co.uk/) │ └──3.41 MB (00.55%) -- (9 omitted) ├──163.72 MB (26.53%) -- heap-unclassified ├───96.54 MB (15.64%) -- layout │ ├──62.89 MB (10.19%) -- styledata │ └──33.65 MB (05.45%) -- arenas ├───28.32 MB (04.59%) -- storage │ └──28.32 MB (04.59%) -- sqlite │ ├──17.94 MB (02.91%) -- urlclassifier3.sqlite │ │ ├──17.86 MB (02.89%) -- cache-used │ │ └───0.08 MB (00.01%) -- (2 omitted) │ ├───6.75 MB (01.09%) -- places.sqlite │ │ ├──6.44 MB (01.04%) -- cache-used [4] │ │ └──0.31 MB (00.05%) -- (2 omitted) │ └───3.64 MB (00.59%) -- (11 omitted) ├───20.51 MB (03.32%) -- dom ├───10.80 MB (01.75%) -- images │ ├──10.36 MB (01.68%) -- content │ │ ├──10.30 MB (01.67%) -- used │ │ │ ├───6.47 MB (01.05%) -- uncompressed-nonheap │ │ │ ├───3.72 MB (00.60%) -- raw │ │ │ └───0.11 MB (00.02%) -- (1 omitted) │ │ └───0.05 MB (00.01%) -- (1 omitted) │ └───0.44 MB (00.07%) -- (1 omitted) └────1.20 MB (00.20%) -- (4 omitted)

Other Measurements

 0.33 MB -- canvas-2d-pixel-bytes
 0.00 MB -- gfx-d2d-surfacecache
 0.00 MB -- gfx-d2d-surfacevram
 0.01 MB -- gfx-surface-image
 7.38 MB -- gfx-surface-win32

553.08 MB -- heap-allocated 568.44 MB -- heap-committed

 3.61 MB -- heap-dirty
18.92 MB -- heap-unallocated
       2 -- js-compartments-system
      30 -- js-compartments-user

138.00 MB -- js-gc-heap

19.96 MB -- js-gc-heap-arena-unused
 0.00 MB -- js-gc-heap-chunk-clean-unused
 8.71 MB -- js-gc-heap-chunk-dirty-unused
  20.77% -- js-gc-heap-unused-fraction

643.61 MB -- private 656.84 MB -- resident

 0.30 MB -- shmem-allocated
 0.30 MB -- shmem-mapped

811.62 MB -- vsize

I can't deal with this! I've never had a problem with browser memory, but I'm now getting pop-ups that firefox needs to be restarted and it's disrupting my work. I've read the replies in the support forum, but I'm not tech savvy, and honestly don't understand why I should have to be to use firefox.

This computer is an older PC, running Windows XP Service Pack 3. I also have an iMac, which I could be using, but I want to use this one at the moment. I have firefox 8, but no idea when it (or any subsequent updates) was installed. It does that automatically. The only plugins currently enabled are Java Platform SE 6 U30 and Shockwave Flash 11.1.102.55.

I had 2 tabs open: my google home page and Yahoo mail, while I was doing something in Photoshop Elements. Yes, Photoshop uses a lot of RAM, but the browser shouldn't be using more. I had the tabs open for about 45 minutes when I got a pop-up from AVG to restart firefox. I took a screenshot, which I hope will show up below.

I closed Photoshop, and firefox was still climbing. It was at 299,168K+ when I restarted to be able to post this message. This is nuts! I currently have a tab for gmail open and a tab for this page and firefox is 167,060K and climbing and plugin-container.exe is 30,472K. Help!

Is there a way to go back to whatever version I had last week?

I am having the same issues and it is very annoying. I have a windows 7 Dell laptop with 4GB RAM and a 500 GB hard drive. Firefox was working great. Last week Windows automatically downloaded some updates. Now Firefox 8.01 is agonizingly slow and when I click on a Tab or link it does not always respond. I checked Task Manager and Physical memory was up to 75% or more. I closed some tabs and restarted Firefox and now physical memory is at 35%. It seems that if I leave it open the physical memory use climbs. Up until recently I had as many as 30 -40 tabs open with no problem. Now even with just 8 tabs open Firefox slows down.