This a long and old thread, it is probably being ignored now by most helpers. So just some personal opinions, backed by a few links:

• There is general advice on high memory usage
• I think many agree Firefox 4 has too many memory problems, but they may now be multiple and difficult to track down problems, and it is unlikely that any will be fixed in firefox 4.
• Firefox 3.6 may be better than Firefox 4 so consider
  • temporarily downgrading to Firefox 3.6 see installing previous versions of firefox
  • or upgrading to firefox 5, which is now in beta release - so may have some problems - but if you wish to try it read first it is then found here (Once you are on firefox 5 you can actually swap channels from the user interface by using about firefox.) Some memory problems in firefox 4 have now been fixed in firefox 5.

If you genuinely want to help and to find a solution to an individual problem it is probably best to start your own thread, and be prepared to do things like run in safe mode and run tests that may be required by those trying to fix bugs. (By all means link any new thread back to comments you have already made here.)

If you just want to provide feedback about problems, that should be brought to the attention of developers then use the feedback button, or the link: http://input.mozilla.com/en-US/feedback.

PS

You may also want to watch for multiple instances of plugincontainer running, that is a current known bug, and can even occur for disabled plugins !

I was having this annoying problem when I was using Firefox at work. After I changed some values in "about:config", memory problems never happened again. Those values are:

  *  javascript.options.mem.max: Its default value is -1, what I guess means automatic or unlimited. After some testing, I decided it's good to modify it to 50000, a value that appears to be in KBytes. Feel free to raise it to a proper value for you.
   * javascript.options.mem.gc_frequency: Its default value is 300 (seconds?). I changed it to 5. I did not realize any overhead.

After those modifications, I started to realize that Firefox released about 5 megabytes of memory every 5 seconds and never started to take all my memory again when accessing GMail (I use it during the whole day) and other sites that like to abuse of JavaScript.

I got my coworker to change this values too and he says it worked for him. It makes me think the memory leak problem is solved!

For testing purposes people can access the "about:memory" address. the "js/gc-heap" shows how much memory the JavaScript heap is using.

I hope this is useful.

Sorry for my English. It's not my native language.

Yea I was getting slowdown problems FF 3.x on a 5 year old Mac, got a brand new Mac running Firefox 5 and am experiencing much the same behavior.

It will start with 558Mb of real memory with a set of 8 windows open, eventually, after surfing for a couple of hours that same set of windows is using 1.2 - 1.4 gig of real memory and the system free ram is near zero, causing 1 minute long beachball icon pauses. Quit from this state can take 10 minutes, with a script error popping up during the exit, usually that error is:

A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete. Script: resource://gre/modules/XPCOMUtils.jsm:271

I assume it's just a side effect of the memory shortage.

Note the techies have been making improvements with the newer versions of Firefox. Unfortunately Firefox 4 was rather problematic, but that is no longer supported. Firefox 7 & 8 are already being tested diagnostics are being improved, and memory usage problems are being looked at and changes are being made. (Changes are probably not being back ported to earlier versions)

One of the developers is blogging about the progress; and trying to make a boring technical subject understandable and interesting.

Note the new diagnostics are starting to include buttons to help reduce memory usage. It may be worth considering giving the Beta or Aurora channels a try.

To be totally honest, Firefox seems to be garbage lately. Actually, for a long time. I'd say for the last 4 years or so it's really sucked because of the huge memory leaks and the crashes. IE has NEVER crashed on me, and there's no memory leak. Right now I have one FF window open and it's using 648mb of memory. One IE window open is using 48mb of memory. If I leave both open and come back in two hours, IE will still be using 48mb, while FF will be up to around 2GB or so of memory. Why? And why does it crash all the time? It can't seem to handle that many plugins and I always find myself switching to Opera or IE to surf certain sites either because FF is slowing my system down too much, or it keeps crashing on certain pages.

  To be honest, if Chrome had the option to tweak the settings to the extent FF or IE do, I would uninstall FF altogether.

You probably are now unlikely to get answers in this long thread; although you could read through it. If you really want to figure out where Firefox is using memory use Firefox 6 or newer and key about:memory into the location bar, then click the green arrow.

The resulting page will

• display more info as tooltips on mousover
• has useful buttons that may reduce memory usage
• is designed so as to be pastable if you want to discus specifics

If comparing with IE I suggest

• use the same page or set of pages
• use firefox's safe mode and disable any unused plugins
• (You may need FlashPlayer for your chosen pages, but note there are some reports in this forum of Firefox 6 crashing or hanging with Flash Player, and difficulty in upgrading FlashPlayer correctly)

If you want an answer regarding your problem you wolud do best in my opinion to update all your plugins and extensions, and then post your own question in a new thread, and be prepared to experiment, possibly including using the latest Aurora or even Nightly channels to see if that resolves any problems.

I've been using Firefox since I finally bailed on Netscape Navigator, which I stuck with far, far too long.

I'm starting to feel the same about Firefox. For a couple-few years now, I've taken to googling "firefox memory leak" about once a week, as I have to deal with restarting Firefox several times a day.

Every time, threads are peppered with this or that about developers fixing leaks with the next version. (I often land on this here thread.)

Nowadays, I get a brand new version of Firefox every week, but the memory leaks remain.

I like to have many windows open at once. Over a dozen is the norm. (I seldom use tabbed browsing. I've tried it. It just doesn't work for me.)

Firefox starts to appreciably slow down at 1.2 GB of memory for me. By the time I hit 2.0 GB, it's time to restart the browser. This is often just a couple hours after the last restart, and very little is changing.

I think a lot of it is Flash. But Firefox should learn to handle that better than it does. Youtube videos just kill Firefox for me. They suck up the juice like crazy.

Yes, I've tried creating new profiles. It's a big hassle to do routinely, though. Haven't done in over a year.

I keep all my add-ons updated. Main;y, though, I just use Greasemonkey (with less than a handful of scripts that are very specific to limited locations) and AdBlock Plus.

Finally spent some time using Google Chrome this past month. Not just popping in for a sec, but really using it, lots of windows open and all.

Using Chrome is a revelation. It feels much like when I started using Firefox.

I feel like wrestling with Firefox's memory issues is just a dead end. I could continue to google the issue weekly, getting pointed six ways from Sunday, running around in circles to apply workarounds suggested on message boards. But I'm tired of workarounds. I'm tired of working on my browser, instead of just using it. I'm tired of being told it's something I'm doing wrong. (Yes, I still have the issue in Safe Mode, without plug-ins.) (Yes, my few plug-ins are all up-to-date.) (No, I'd really rather not use tabs.) (I like having so many windows opened because that's what works for me. In Netscape Navigator, I could routinely keep 25 windows open, with few memory issues; asking Firefox to do the same is not asking too much.)

I think this is goodbye.

I'm now running Fx 6.0.2 on Windows 7. I usually have 3 windows with 3-8 tabs each running and seldom restart either Fx or Windows. Yesterday I noticed it was taking forever (well, maybe 30 seconds) to open a new tab in the current window (e.g., by clicking on a link in an e-mail).

Long story short, I used Task Manager to find that Fx was up to 500M page faults and using several hundred MB of memory. When I went to bed last night, I restarted Fx, just one window, and left it idle. This morning it was up to 202MB.

I haven't yet done any diagnosis on my own, but will start this evening. I just wanted to tell anyone who is listening that the problem still exists in Fx 6. It was severe a while back (in 4, maybe?) but seemed to have been fixed for some time. But, like the Terminator, it's baaack.

I started Fx last night at 21:30. Task Manager showed initial memory at 100,880K, slowly increasing to 125,124K in about 7 minutes. I restarted Fx in Safe Mode at 21:39, and with only the Safe Mode page showing Fx was using 86,480K. This morning at 07:00, Fx was up to 170,108K.

Interesting thread and it's the top google hit for "firefox unstable memory hog". I'm not as technically adept as many folks posting here, but, while I acknowledge I have an older pc, it's obvious that Firefox is coming up short on meeting expectations set long ago when I became a Firefox fan. I routinely have hotmail and streaming netflix open -- that's about it -- and Firefox routinely takes over my pc and/or chokes up. Frustrating obviously, and I hope there's a good competitor out there. I tried to break away from Firefox once before for the reasons noted here, but had to come back. If there's a stable browser out there for my minimal needs, I'd like to find it and will force myself to adapt. Sad state for Firefox ... pick any version over the last two years or so ... I've tried it.

Well after the last 3-4 months of just having to reboot my pc to get some speed back and after a format reinstallation and disabling AV/Trying other AVs... stopping Sabnzb/utorrents was almost about to give up untill seeing this thread...

Firefox is definatly the problem, I noted alot of people are saying its the addons and I think this is very true. If I even have 3-4 tabs/websites open after a few hours my pcs ram usage goes thru the roof to 2.5-3.5gig, and im left wondering why my pc has gone so slow for a quadcore/4gig pc.

As soon as I disable firefox the ram usage goes back to 500-600meg and the pc speeds up.

I have so far deleted/disabled all my addons but left Adblock and noscript on, but yup its still occuring so its definatly one of these addons causing the massive ram leak !

Gonna disable one at a time and find the culprit.... one things for sure installing opera and your blown away by the speed and performance of it, its very hard to not go to it 100% but I do like noscript/adblocker since it does such an awesome job at blocking viruses/malware/popups.

Will re update later on !

it may be worth remembering this thread started a many months ago with Firefox 3.6 but firefox 7 is now on release with Firefox 10 on nightly.

this is with firefox 7.1 the latest updated version just few days ago :)

I have disabeled adblock plugin/addon, and will launch several tabs/websites and see if firefox still kills my 4gig ram making my pc un-useable after a few hours.

Ill report back soon im sure its adblock or noscript causing the ram leak for me...

RP3X if you do find something causing a memory leak I suggest you start a new thread, (and link to it from this thread, so no one misses the post) it may then be worth filing a bug about the problem, (if it is not already a known problem). Bugs are normally filed only for firefox problems, but I think an exception is made to includes problems associated with widely uses software or sites.

If a specific add-on or plugin is implicated, the software's forum or developer will no doubt also be interested.

While I would prefer be browsing via a trouble-free Firefox, I switched over to IE early on today once I saw signs of Firefox overburdening my pc yet again. And while the age of my pc remains evident while surfing -- using hotmail, streaming music, and streaming movies -- I must note IE managed the memory with no forced browser shutdowns or pc reboots necessary ... it's managed it to this moment in which my pc is not having a cow as I simply type text into this forum reply ... I guarantee any readers interested (i.e. Firefox representatives) that my pc would be having memory conniptions at this very moment if I had used Firefox for the latter half of today. Firefox is literally shoving me toward being a reluctant IE fan.

If you feel that way by all means use IE, as your only, or one of your browsers.

The pity is the users with problems often have highly customised Firefox setups, and so loose many benefits of Firefox, and often have not tried to follow the advice of

• upgrading to firefox 7, with all other related software also updated
• trouble shooting ie safe mode, default theme, and all plugins disabled
• starting their own thread by asking a question and solving their own problem possibly using firefox's recent and sophisticated about:memory feature

Got it. The customized aspect doesn't apply me, so my options are to (1) upgrade Firefox yet again as a proposed resolution to a consistent problem going on for roughly a couple of years (side note: the start of this thread refers to a 2 to 3 year old version as a fix) ... I'm sure the upgrade answer has been provided countless times over this years long time period ... it hasn't worked yet, or (2) become a Firefox techie, or (3) close -- and ignore -- an existing ticket by opening a new ticket. You've provided the quintessential help desk response ... (1) punt by replacing the pc and/or program, (2) blame the user, or (3) adminstratively close the ticket. Perfect, and congratulations!

You do seem to understand the problem

1. Upgrade
   
   • Yes you do need to keep not only firefox but other software up-to-date.
   • with Firefox's current rapid update cycle the outdated unsupported versions are just that, unsupported, you will need to update to get any fixes and improvements (current transitional exception Firefox 3.6.23 is still supported)
2. Become a firefox techie
   • That helps ! as does understanding the basic troubleshooting Firefox is highly customisable, something many users like and use, the downside is some of those customisations may cause problems
3. ignore this thread start a new one
   • threads, tickets as you refer to them are intended for individual problems, the first poster is able to provide significant detailed information that helps solve that individual problem
   • this thread is now old,
     • there is a mismatch between the original post and title and the problems being discussed
   • start a new thread about your individual problem, try to get an answer to your own problem - even consider filing a specific bug for developers to solve something very specific
   • want to vent frustration ?
     keep posting here,
     many people will see it, no one is likely to give you a useful individual answer, developers are unlikely to ever see the posts, but you may feel better.

Very true the issue seems now resolved now that I disabeled the firefox addon called adblock... I find it quite odd something that ram draining has not been fixed/mentioned but ill try to notify them, for now my firefox is back to normal :)

So just like someone mentioned on this thread its good to check out the addons they can be causing the issues.

Thanks RP3X,
good to have a comment offering a potential solution to part of the problem.

Start a thread about adblock and memory leaks, the information may help others. If the problem is confirmed by others then maybe also contact the adblock site/developer, and post a comment on the blogsite: http://blog.mozilla.com/nnethercote/2011/09/07/on-vacation-september-12-to-october-17/

If the particular problem is widespread because it is a very common not only the add-on team but also firefox developers may be interested. Certainly the firefox team investigating memory leaks are interested in specific sites and software that can be shown to cause problems. If you start a new thread post a link here so other readers of this thread do not miss it.