Firefox 3 Hogs Memory Like Crazy

When Mozilla released Firefox 3 as a public release candidate, it was supposed to fix a bunch of memory leaks and use less memory. In fact, it reads:

Memory usage: Several new technologies work together to reduce the amount of memory used by Firefox 3 over a web browsing session. Memory cycles are broken and collected by an automated cycle collector, a new memory allocator reduces fragmentation, hundreds of leaks have been fixed, and caching strategies have been tuned.

Technical, yes. Real? Not really. While I have heard from others saying that Firefox 3 is running lean and mean for them, I have heard from many others saying it is just as bad in the memory department as Firefox 2.

Check out this screenshot from my own Mac Pro running Firefox 3:


Yes, that’s 550 MB of RAM in use.

Now, I’m fully aware that the plug-in functionality of Firefox can lead to this issue. It is non-Mozilla code which is in use in the browser. But, I used pretty much the same selection of plug-ins with Firefox 2 as I am now with Firefox 3 and this is about 150 MB more memory than I had ever seen Firefox use previously.

Plus, if you have to steer clear of plug-ins to keep Firefox running correctly, then that is a stupid tradeoff. One of the primary “selling points” of Firefox is the ability to use plug-ins.

I have tried the RamBack plug-in. It shaved maybe 12 MB off the memory usage, but who cares. For all essential purposes, it doesn’t work.

I’ll continue to use Firefox, but thank God I have a bunch of memory in this system. Looks like I’m going to need it.


  1. Well, how many tabs tid you have open? If you have 20 tabs with heavy flash animations and so on, what do you expect?

  2. David Risley says:

    Dude, do you think I woulda posted this post if I actually had 20 tabs open? I’m not stupid.

  3. Well, something stupid is going on. So if it’s not you, it must be you computer/OS cracking things up. I for one sake have 14 plug-ins on my beloved Firefox, and have in rare cases been up to 100 mb of ramusage at most. And that’s with around 10 tabs open.
    I’m just saing that a ferrari isn’t that cool if my grandma’ is driving it. 😉

  4. Wootpwned says:

    I’ve officially removed PCMech off my daily visiting bookmarks after reading this article. Completely unfounded, and there’s reasons why software enters a Beta stage. Considering your getting something for nothing, and works better than well-known integrated (effectively paid-for) browsers, I don’t see where you get the right to complain.

    This article is based on ONE user experience, in which it could simply be related to a SINGLE add-on that the user is operating. Zero research, zero facts, zero creditibility.

    And with that I say Goodbye to PCMech. You are no longer a daily source of informed I.T. related news.

    • David Risley says:

      Suit yourself. But, here’s the thing. This website is owned by ONE user – me. This is a blog site where my viewpoint does make its way into a blog post. I’m not trying to pass this post off as news. It is my experience and I think I made that very clear.

      If you cannot read a user opinion on a blog without cracking up, sorry.

      • Wootpwned says:

        If you’re not classifying PCMech as a news site, then why do you have a website dedicated to blogging?

        Using your methodology, they are one in the same? If this was intended to be a “blog” and not trying to pass itself off as a news story, why wouldn’t you post it on your personalised blog site instead?

        Fact is, you have a larger reader-base, yes. A majority of your content is reporting news events, except this one, which is a stand-alone personal opinion. People, such as myself, read this as “news”, not an opinionated blog.

        • David Risley says:

          My personal blog is about what I do. This blog is about tech. BOTH are blogs, about different topics.

          And opinion is nothing new at PCMech. If you think so, you haven’t been around here long enough.

    • Wootpwned, I just gotta say.. (*sniff*) it’s so sad to see a hide-behind-the-monitor with a netspeak retard name leave the site. You shall be missed. Well, not really.


      Dave’s FF wasn’t beta, it’s an RC. Know the difference.

      And do you know of anyone else that (foolishly) pays for a web browser? Seriously? Who *doesn’t* get browsers for free?

      And yes, you’re right. The fact our readership keeps growing on an almost daily basis means we totally suck. You’re so right. We’re just terrible at I.T., but hang on.. we don’t do enterprise boring-o-rama I.T. crapola.. or even things related to I.T.

      Yeeeah, safe to say you talk out of a place where the sun doesn’t shine. Buh-bye.

  5. David, there are many tweak to reduce Firefox 2 & 3 memory usage, but there is only one solution I’ve found called, Firefox Memory Optimizer (full description of the program on this page). I have been using it for over 3 months now, and it works GREAT. I currently have six tabs open, and FF is running at a cool 244-3500k, and the program itself is using only 1500k. Sound too good to be true? Try it! It’s free, small, virus free. and works without any reduction of FF’s performance. To see how well it works, run FF, jack the memory usage up as high as you want, then start the optimizer, and try to not let your jaw hit the floor. I don’t know how it works, or why Mozilla hasn’t incorporated it into FF, all I know is that is saves my ass because, I don’t have much memory. In fact, I am embarrassingly only have 384k, yet this amazing little program allows me to run FF without issue. Let me know what you think.

  6. Hahaha, I like the analogy. I sure hope that the leaks are fixed globally. I hope it doesn’t become like FSX, which runs really well and some computers and really poorly on others, completely independent of hardware.

  7. oldtimetech says:

    I took a photo of my resources and I’m on a laptop with 3gb of memory and I’m only using 227.9 and my system considers it sleeping and I’ve been on it all day…interesting huh?

    Darn…couldn’t figure out how to attach the screen shot.

  8. You removed my post concerning Firefox memory optimizer? Why? I have run IE7 & 8, Safari, Opera, and a few others, and not found that any are overly superior to the other when it come to memory, and CPU usage. I’ve been using Firefox 3 since i9t first came out, run 15 add-on, and multiple tabs and NEVER had anything like you experience. I think the other guy was right, YOU did something, or your system. Or, maybe your issue with Firefox is personal, or financially motivated? Quite possibly, you’re an idiot, and a self-proclaimed PCMech!

  9. Alan David says:

    Interesting. I just installed in (more or less to see what gives) and it’s running about about 1/2 the memory load that Firefox 2 was. I was hoping to run them both side-by-side but even installing in a different directory seems to have obliterated my installation of Firefox 2.

    But when I checked, FF2 was using about 187,000K (two open tabs, 16 installed plugins). FF3 is using 77,000K (two open tabs, 9 plugins as 7 are not compatible with FF3). Sure seems a hell of a lot faster that’s for sure. I’ll play with it for a while – see if it’s a keeper.

  10. JimmyDabomb says:

    FF2 averaged 150megs for me.
    FF3 has been averaging 50 megs.

    If your data is valid with no real way to reproduce, so is mine. 😛

  11. Personally Firefox 3.0b5,rc1,rc2 all use noticeably less memory than FF2.0 used to. I think this is the best browser I’ve ever used. Maybe its a problem with Macs? I’ve never heard of anything like this though.

  12. So, you’re saying you’re upset at Firefox for allowing people to write crap plugins that hog memory? Huh?

    Try pointing the finger of blame at the plugin writers. Or, if you want to take your argument down the reductio ad absurdum route, blame OSX for allowing a program to take that much memory.

    FWIW, my Firefox is sitting pretty at 70 megs with 7 tabs open across 2 windows. No clue what you people do to bloat yours.

    • David Risley says:

      I USE it. That’s what I do. I am online 24/7 with this browser. I put it through its paces more than most.

  13. I just checked mines and it reads 112 MB.

    • I checked mine out of curiosity, and version 3.0.7 is using between 95-105MB with 4 tabs and 13 plugins. There’s gotta be some explanation for how it can eat up 550.

  14. I find this a very simplistic and bad review of the founder of this site. Much too little detail to get any useful information and when someone comments on the amount of tabs: I’m not stupid.
    Also the link to proof that ‘many others’ have the same problem onlt contains one use who seems to have a problem, but also does not want to reveil how he tested Firefox. So to say that FF3 is still a memory hog based on this, is kind of … stupid?

    All in all: a very narrowminded review which luckily is not representative of most of the Firefox 3 users which are very happy with it.

  15. Seems to me that most people think Firefox 3 uses less memory than previous versions, so either you are encountering an odd bug with the memory management (so you should be reporting it, since these things are expected in beta 😉 ), or the plug-ins you have are not fully compatible with it.

    “Plus, if you have to steer clear of plug-ins to keep Firefox running correctly, then that is a stupid tradeoff.”

    Would agree, however it’s not really fair to blame Firefox for 3rd party code, in the same way you don’t blame your Mac for the memory used by Firefox. Putting pressure on the plug-in developers would help resolve the problem, if that is what is causing it.

  16. Out of curiosity I checked my system. I currently have 3 browsers running…here’s the details.

    Opera 9, been open for about 36 hours, one window open broadcasting to ustream – 37Mb
    Flock 1.1.4, open for 1 hour, one window playing a Flash stream – 74Mb
    FF3 (just updated to latest release this morning), open 1 hour, one window displaying a static page (this one) – 92Mb

    Everyone knows FF has memory leaks. That doesn’t take away from the fact it is a great browser, arguably the best general purpose browser. Big deal if it uses a lot of memory…just close and reopen it once in a while.

    My hat’s off to Dave as well. To blog is to put your opinions out to the world knowing that some will get bent by them. It takes balls to do that. Don’t like it, go to cnet and read the “objective” paid for reviews and articles.

  17. PointlesS says:

    wow post a single bad user experience about firefox and everyone is quick to point out that “it doesn’t happen to me so you’re wrong”…it’s just stupid

    firefox 3 uses just as much memory as firefox 2 for me…with only this page open it takes up 95megs with no plugins installed…I love firefox as much as the next person…but seriously…someone with a lower end pc…like my brother who has xp and 512megs of ram might not even find firefox usable…and if other browsers have significantly less memory consumption then what’s the incentive for him to run it? I know it’s still in beta but with it getting rc status…there’s clearly some issues still remaining…by comparison ie takes up 35 megs and opera takes up 28

  18. I must apologize for the rude comment my roommate posted, in my name. I left the browser open and on your page, and in her marijuana and tequila induced frenzy, she thought it was funny. Sorry. If anything, it should serve as a reminder to say not to drugs, and yes to Firefox. By the way, she uses IE6, if that tells you anything. Nonetheless, no one, including you, commented on my post, and it’s making me wonder if I’m crazy, or stupid. Does no one but me realize the value of the this little tool, or is everyone else using a Mac?

  19. I have 4 OS’s loaded on different drives:

    XP SP3
    Vista x64 (for 4gig usage in graphics apps)
    ubuntu x64
    Kubuntu x64(testing new KDE 4.0.4)

    In all of these….and oddly enough in Vista, FF3 RC1 bests FF2 for mem usage(granted not all my plugins function yet). I have tried real hard to push FF3 to use loads of mem, and cannot, I even managed to crash it on a few sites(MyCast.orb still will not function properly in linux). But none hit the ceiling you have shown….so I’d have to say the earlier assessment of it’s you or your OS may have some merit.

    I noticed your reaction like most MAC people was “it’s not my OS” like you can somehow guarantee Apple perfection when even they cannot. please, be objective and actually delve into this….from a ‘technical’ standpoint, not some arrogant fanboy position, the PC user realm has had enough of that kind of backwards thought progression.

    Here we are twenty years later(OS, GUI, and user system speaking), still begging for basic features from our tools provided either by major corps, or the free options.

    Both to blame for this lack of advancement. it’s like waiting twenty years for the adjuster wheel for your adjustable wrench(spanner), sad, truly sad, so much for innovation. And most of this can be explained by corporate greed and ignorant fanboyism, the two leading factors holding back real operating systems that just friggin work.

    sigh, but I rant, good luck tracking that leak down, my guess is it’s BSD based as I’ve noticed with some other Linux ports on OSX.

  20. Empyrean says:

    That is real odd, I’m running FF RC 2 on Vista and I get about 86Mb RAM usage. Could be some sort of bug that is related to OS X, I for one have my fair share of bugs with FF 3, one being that RC 2 absolutely refuses to install flash.

  21. I’m sorry to hear about your memory hog problem.

    I was actually surprised by the amount of memory Firefox 3 consumed. I tend to open way too many tabs (up to 90 – I kid you not) and it wasn’t unusual for Firefox 2 to take over 300 M..

    So when I first tried Firefox 3 I got so excited about the lack of memory consumption that I went crazy adding extensions to it, hahah.

    As of now I have 44 enabled extensions(most of them, technically, aren’t even compatible with FF3) and 47 tabs open. And firefox 3 is taking up 197 M. (So far I’ve seen it go up to 280 though).
    I gotta say I expected it to reach 200 M on the 20ish addon… but so far it’s been holding up pretty well for me 🙂

    Oh, the “Stylish” addon seemed to make firefox CPU hungry here, so I had to deactivate it… Perhaps you’re using a similar addon that might be the problem?

    • @Nayelianne

      Just curious.. can i know how come you have 47 tabs opened?

      • @uvberot
        It’s my incredible ability to fail at multitasking, hahaha. Probably a bit dispersive too.

        I finally got an addon (Session Manager) that helps me keeping just relevant tabs open. Got 20 atm), but before that…

        I just used to find interesting sites or articles(they’re like a never ending chain of interesting links) that I didn’t want to lose (and if I bookmarked them, I knew I’d never see them again)…but I didn’t want to read them at the moment, so tabs just begin to pile up :/

        I guess I’m just that messy. 🙁

  22. This review is like everyone is saying. Its crap. In order to replicate what it would take to use over 550mb on FF3 with only java and flash player installed, I had 15 tabs open all to the myspace login page that was advertising the new batman movie, and each was running the video in a difference sequence. So stop being retarded. ANY web browser is going to use tons of memory when running multiple videos at once or other plugins. People use firefox for many reasons, the main reason, it works better with streaming video and sound. I’ll trade another 20mb if it means fewer cache refreshes.

  23. Firefox 3 is killing my mac. so much so that i never noticed it on firefox 2, but over the last few days i had to google if firefox 3 was a problem because of how slow it is.

    it has noticeably slowed down my computer, almost to a crawl. i have 4Gb of memory in my mac book pro.

    i’ll try some of the options here, but don’t lambaste the author as he is right.

    btw, i’ve been a unix/linux systems engineer, network engineer, and java app server engineer for over 8 years now … i know how to track down a memory hog culprit. my grandmother, if she were alive, could have figured it out.

    anyhow, safari works better with regards to memory for the time being.

  24. Well you are not the only one having problems with firefox 3. For the record I LOVE firefox but FF3 is crashing my computer using 99% of the cpu. I never had any of these problems with FF2.

    Have tried many ways to fix this as I am loosing my mind. Am this close to uninstalling and hoping to go back to FF2

  25. I’d suggest if you really are having problems with FF3, when was the last time you’ve cleaned your system? Files may be corrupted. Left over dll files from uninstalled programs loading in the background from a bad uninstall, plus many other hidden problems. Sometimes its best to backup and do a full reformat and install if you are using XP. It might help for Vista as well. Sorry, not a MAC user so I don’t have any advise other than to sell it and get a PC.

  26. Wow, I thought I was the only one as well. FF3 is using waaaay too much memory with me as well. I’ve just got 3 plugins and hardly use more than 5-6 tabs. Even when you exit it still keeps running. Then I use procexp to kill it and its there I can see how much memory its using up.
    Sadly I’m back to FF2 now.

  27. I have seen this problem on my pc too

  28. I’m using FF3 on my PCs(Home & Office) and I have same problem too. Sometimes, FF3 is freezed and only one tab uses more than 200mb.

    I’m considering switching to IE seriously…

  29. Abhinav Kumar says:

    I have tested all three browsers. I left Safari bcoz it is universally known that Safari is a memory hog on Windows.

    Firefox 3.0 | Internet Explorer 7 | Opera 9.51

    Test 1:
    Tabs Opened:
    Yahoo Answers
    Orkut Home>Orkut Scrapbook (> means navigated)
    Orkut Communities

    Browser: Memory/VM Size
    Firefox: 63 MB/58 MB
    IE: 95 MB/101 MB
    Opera: 71 MB/75 MB

    Test 2
    A Java Chat Applet
    Computer World

    Firefox: 162 MB/170 MB
    IE: 292 MB/344 MB
    Opera: 207 MB/246 MB

    Test3: (Silverlight)
    Microsoft Silverlight Showcase (

    Firefox: 42 MB/43 MB
    IE: 49 MB/56 MB
    Opera: Not Supported

    CPU Usage.
    while viewing a Youtube video (Adobe Shockwave Flash Video)

    F: ~20%
    IE: ~25%
    Opera: ~45%

    The best way to prove something is to test yourself.
    You can test yourself by opening these pages.
    Don’t forget to enable VM Size column in Task Manager. VM Size shows how much resources the program is actually using.
    During Test dont ever minimize any windows.

  30. R. Decher says:

    So I got sick and had to acknowledge that Firefox 3 has become a memory hog.I googled “Firefox 3 memory Hog” and it led me to this site.
    I am a mac user, and I preferred Firefox over Safari, due to its add ons. Nevetheless I usually navigate using Firefox, Safari and Opera simultaneously, and with multiple tabs. And guess what, my machine handled them nicely when Firefox 2 was installed.
    Now with Firefox 3, the fan just goes nuts, and when Firefox is running at 110% I have to turn it off. Safari and Opera remain stable, which pisses me off, since Firefox is still my preferred browser. I have a feeling one of the add ons is messing things up.
    this is my list of add ons:
    delicious bookmarks, forecast fox, downthemall, readitlater, gspace, foxclocks, and a couple of dictinaries.

    Regarding the review : i think using 500% is exaggerated. I would fear my machine would blow up beyond 250%, so I think you are pushing it up deliberately and suspiciuosly to state a point. Nevertheless, the point valid.

  31. R. Decher says:

    started happening again a few minutes ago. Only had two tabs open, but one was :
    turned the tab off and … voila!
    Nevertheless annoying.

  32. I came to this site after realising that my computer had been slowed down by FirFox 3.

    I can’t believe the hostility that your post has received. You had a bad experience with FF, you even got a screengrab and wrote about your disappointment, which then received undeserved criticism that your post wasn’t scientific. I don’t use FF in a scientific way, I go to sites that I want when I want, if it was tested in a scientific way the results wouldn’t be accurate for real-world usage.

    Anyways, I checked Activity Monitor while writing this, with FF consuming 615MB RAM, with two tabs open (yours, and campfire). I took a screengrab which can be found here:

    As you can see I have web developer extension installed, I also have Firebug and Foxmarks installed. Nothing spectacular. Firefox has now been open for about 50 hours. But *I know* if I restart wihtin a couple of minutes it will already be exceeding 200MB, then grow and grow.

    I’m running OS X 10.5.4 on a first gen Macbook with 2GB RAM.

    I have seen consistently good reviews about FF3 on the internet, beating it’s competitors in memory usage, but that’s mostly been for Windows. I think that there is something seriously wrong with the OS X build.

    For me FF3 is slower in all departments than others such as Camino, Safari, and Opera. It feels sluggish and bloated. So much so that when I visit lengthy web pages such as Django’s API pages the scrolling becomes snail-slow and jerky. Camino also exhibits this behaviour leaving me thinking there is something wrong with the Gecko engine (on OS X). Safari and Opera let blitz through pages on the web just fine – but then Safari doesn’t have Foxmarks, and Opera is butt ugly (on OS X), and none have web developer of firebug extensions – something I have come to rely on.

    Keep up the good work and funny captions on your screen grabs!

    BTW, just before I wrote this FF was actually consuming 650MB RAM, for some reason it dropped.

  33. Mentioned in a previous comment that I found Firefox slow and cumbersome when scrolling through long web pages. I get this on all me Mac computers. Don’t know what it is like on Windows though. Perhaps some people reading this can test by visiting:
    Just scroll down the page. If you have the same problem as me the scrolling will be juddery and slow and generally unpleasant.

    can’t believe I can’t even scroll a lengthy webpage without performance suffering, this is one of the most basic things of web browsing. Also wanted to note that during such scrolling CPU usage hits 100% for one of the two CPUs in my computer. This is appalling, by the same token safari is smooth and consumes about 20% of one CPU – a fifth of firefox!!!?? WTF is wrong with FF?

  34. I didn’t read every single comment, but I’m pretty sure I have everyone beat. With 4/5 tabs open and 7 add-ons, I hit 1.3Gb of usage on an XP Pro system with FF3.0.1, and 50% cpu utilization. I have 2Gb of memory and between FF and iTunes my computer was all but dead in the water. This only appears to happen after FF has been open for awhile, even if I am not actually using the computer. I do suspect it is an addon causing the issue and I will uninstall them one-by-one until I find the culprit. Also going to check out that Firefox Ultimate Optimizer that Brian mentioned. I still think FF is the greatest.

    Thanks for the post. I am curious, by now you are probably not running the RC version. Have your figures improved since?

  35. Well, how should it be explained if I opened only google, no tabs, and it took 103MB memory after I started firefox for a short while?

  36. I decided today to stop using Firefox 3 when I came home and found it had gobbled up 1 GB of memory. At work where I’m a web developer I and my colleagues have found the same thing. It just eats and eats and eats. It’s like we’re back to the IE6 days or something.

  37. well theres your problem right there. your using a mac. dont use a mac and you wont have any problems.

  38. elprrrrrra says:

    hi idk wtf is happening with mine mozilla too the other day i was playing runescape and hearing music on youtube and it almost get to 900,000kb i was like wtf?! it aint supposed to be that much and when i just run it and get on google its get 70mg by the way i am using windows vista homepremiun 32bit x64…. ty ill be watching for solutions

  39. I have the same problem! Even when I close ALL the tabs, FF still consume over 200 MB. I have to restart FF every few days when it reaches 800 MB.

    I also see FF consume a lot of CPU if left running for a week. Maybe it’s Flash that’s eating CPU…but there should be some sort of way to stop that from happening. Maybe something that helps me find the memory leak, and CPU leak. It could be FF, plugin, webpage, or something else.

  40. My scanner says “Firefox Ultimate Optimizer” is Adware.

    Any other recommendations?

  41. frenchuser says:

    Hi ! I don’t know if you’ve finally solved your problem – I give up reading after twenty angry coments ;°) but…

    You are not alone, David Risley…

    I actually have an I Mac Intel Core 2duo 1Go Ram, running on Mac Os X-5-5.

    I download FF3.0.3 less than a month ago because I was fed up with the constant bugs I encountered with the last version of FF 2 (2. something)

    I use it the same way I use FF fom the begining : two or three pages opened with at least 8 tabs on each is a minimum (my record – without intents – is about 80 tabs on a total amount of seven or eight pages).

    At the time when I’m posting (7 pages, 62 tabs) : the activity monitors says : 569,11 Mo MR & 2,47 Go Virtual memory !!!

    However, I have to say that even with a single page opened and a couple of tabs, I quickly reach the same level of incredible activity. Actually – should I say “fortunately” ? – it seems to stay at this level whatever the (ab)use I do with…

    Problem is internet seems rather silent about this trouble, exept with articles talking about the beta version and nearly a year old…

    To conclude, I should point out that the firts versions of FF, around 1.5, let’s say, was running much smoother in comparaison. I think ‘I’m going to forget it and keep tight with Safari instead, even if FF is better designed.


  42. YEP, me too. No probs with FF 2, but ever since I upgraded/DOWN GRADE to FF3, my CPU just locks up after 1.5 hours, and I make sure to NEVER open more than 3 tabs…usually only 2. I am sick of having to REBOOT but IE does not allow me to log in to my remote email server anymore??

    A google search for this problem, led me to here. I thought I must have a virus. Your earlier “posters” from 06/08 are cry baby douchebags.

    Hope someone from FF googles this too!

  43. as i posted here

    Firefox 3.0 is not releasing the memory used by tabs that are closed correctly. I shall be bugging this as soon as i have cleaned up my reproduction steps,.

  44. I downloaded and installed a Windows XP update that fixes a GDI memory leak:

    and after that, FF3 memory has been very stable. I’ve been running this about 3 or 4 days now, and FF3 memory use is OK. So maybe that will fix the problem. I would like to hear feedback from others.

  45. J23, stop pimping your antique Hotfix, IT DOES NOT APPLY TO SP3.

    everyone else getting the issue, vote and validate @

  46. As for that Firefox optimizer, its a load of rubbish, it doesn’t make firefox use any less memory at all, it just dumps it all into the pagefile, which is NOT optimal for any application.

  47. I have to agree with the sentiment of the article. I have installed Firefox 3.0.3 and its a dud. Runs slow, won’t scroll, eats up memory. I haven’t added in any plugs in etc, etc.

  48. A new Firefox update came out today. Maybe it will be better.


  49. Hey Squall,
    All I know is that on SP2, I loaded that windows GDI leak fix, and my FF3 memory use stopped growing by 50K/second (by the end of the day, that was the rate before the GDI fix). Since my last post, I saw it spike one time up to > 1GB, but it’s not a daily thing like it was before. So I think this GDI fix helped my system to some degree at least. Thanks for posting the link to 464648. As for “pimping” — I ain’t got no purple velvet hat!

  50. Something that has helped me, is to start with a fresh install (with all bookmarks moved over – tip, once you replace the bookmarks.html and the bookmarks backup folder, you won’t see your old bookmarks return, until you go to the Bookmarks menu, choose “organize bookmarks” and choose restore).

    Then selectively reinstall your most important add ons. Be selective, and disable all add ons that aren’t needed constantly.

    Then make sure all of your flash/shockwave/realplayer, etc. add ons are using the absolute latest versions.

  51. I have 2GB of RAM.. I only use about 1.2GB or it, but my firefox3 generally runs at about 150-200MB with only one window and one browser.. it probably starts off at about 80GB after a clean reboot, but it only takes a little surfing before it’s idling at 200MB.. no plug-ins. Glad to hear I’m not the only one.

    Mac people are not making this up; neither are we crazy. I have a brand new mini-mac, brand new operating system, brand new copy of FF and am only running 4 extensions (Tabmixplus, History menus, scrapbook, and Adblockplus). After running FF for 12 hours with only 5 tabs open I used 800MB of Ram! Yes that’s megabytes not kilobytes. I am beside myself and rather than snide comments, can someone offer something constructive please.

  53. I am running Kubuntu 8.10 w/ ff3. It was doing fine w/ resources and then wacked out. It stayed under 100 w/ as many tabs open as I desired with no prob, now I have it hitting 5-600 MB w/ 3 tabs open – yahoo mail, iGoogle and, on a little laptop w/ only 750 MB mem – froze it up as stiff as ice. This I tried on Gnome, KDE and XFCE, as I use all three. So in reviewing previous comments I think OS has nothing to do with this piggy, as OSX is unix based also as many are prone to forget. I have another laptop here with XP on it let me take a look too. Well fellow FF users it is only pulling 40 MB w/ the same pages open. What the heck happened to my Linux install? I am back on Opera due to FF locks my Linux laptop now. Dear google when are you going to give us Chrome for Linux! PS I like Chrome due to you can kill a tab w/o killing the app. I did not care for IE8’s “features” Still like IE7 though. Don’t hit me for that one. I tried Safari on my Linux laptop and would use it if it would let me get to my yahoo email! Nothing but security issues. Well enough from me. I am just pleased that misery loves company as I was dismayed with the performance of FF on the linux laptop. It does not do this on any of my other computers. I have Win2k server w/ 4 xeon processor for BU of all my systems and it works fine on that one. I have SUSE 11 on an old turd of a computer and all works fine there too. I just don’t get why FF is different on each computer and install. Some one @ FF needs to PUSH a usage survey out so we can respond. Little intrusive but maybe it would do it.

    Thanks for you site.


  54. Firefox 3 open… 1 tab (this site). Memory usage: 196mb. Only 2 plugins installed: FoxMarks and Cooliris. This is horrid. My 3D game engine I’ve been developing uses less memory than this in debug mode, with physics, rendering, etc running in a populated scene.

    Plenty of talk around about absolute crap for Flash rendering performance, but I do have to chime in that this has pissed me off for a long time. Sometimes I have to shutdown FireFox via Task Manager because a site has 2 Flash ads and a game. I’ve even emailed webmasters about this topic, pushing them to tone down Flash content to better support FireFox users.

    At any rate, I see FireFox going down the bloat path. I’ve been all over the net the last hour reading various topics on FireFox 3 memory usage, and the ratio of good vs bad performance seems to be hit and miss. Though, in my opinion a majority are most likely unhappy about the memory usage.

    I say that in my opinion FF is going down the bloat path, because… well… it is. Lumping on new features, changing stuff around majorly, introducing more memory usage, etc. without making the previous version run pristine seems like something a boat on bloat river would do.

    How long has the Flash rendering been an issue? Even without addons installed, why does FF3 use 100mb+ of memory with only 1 page (in my test, Google) open? I love my FireFox, but I’d love to tell the developers to go suck an egg with the latest version’s memory BS. Yeah, I’ve read their article on how they “improved” things, and understand it for the most part. But I think it’s rubbish.

    It’s nice that random people don’t have the memory issues with FF3. I’d bet they had vanilla (or near) OS installs, and at least 1GB of RAM, nifty CPUs, etc. Well wait a minute…

    I have a vanilla install of WindowsXP Pro SP3. Well, almost vanilla. I have Visual Studio Express 2008 installed, and a few tools like Blender, FX Composer, etc, but nothing that has services running, and none of these apps were open during my “tests”. 1.5GB of RAM, AthlonXP 64 3200+, GeForceFX 7600GS 512mb OC.

    Many can argue, point fingers at David and say he’s a loon… but the fact is, FireFox 3 hogs more memory than it should. Like a bad reflection of prom night that results in you waking in a screaming sweat, punching a flamingo that shouldn’t even be in your state, let alone your bed.

  55. Hi guys, I think I might have found the culprit on this memory issue but I kind of need a confirmation. Any facebooker here?

  56. Oh well, just confirmed my suspicion. I did a test 3 times. Looks like I may have found a sure-fire way to replicate the mem leak problem.

  57. Jay——Give me the secret of the memory leak. Derjyn I never thought of the flash as being a reason. Duh to me, It does appear the the more flash content a site has (and ajax) the weirder the browser behaves.

    On one of my PDA’s I have Iris Browser for test and now it is the default on all my little PDA’s. Now if they could port that one we might all be happy. Such a tiny footprint with a big browser bang.

    I type this from my Opera as I have resigned myself to it’s usage. Not bad but I don’t like some of the features. BTW on the last pushed update to FF3 my XP laptop now wacks out on RAM now and then too. I do have one comment on browsers. TOO MANY FEATURES. Almost makes me want to go back ot lynx. But then the world has changed.

    Lord today keep your arm on my shoulder and your hand over my mouth.


    • Well, if you have a facebook account, go add “Owned!” application. Then, go the application and click on “Owned!” tab (next to “Buy L$1 Friends”). Next, just keep pressing “Next” to view the next images. Just watch how the memory goes from an initial 169 Megs with 5 tabs open to a whopping 500+ Megs. AND, it won’t even go down!! Also, right clicking on an image and opening it in another tab then closing it also adds to the increasing mem. It’s ridiculous.

  58. Jasper Rijkeboer says:

    I just tried the Firefox Ultimate Optimizer that Brian suggested.

    It’s a very simple .NET taskbar application that runs every 10(!) milliseconds. It makes Windows API calls to clean unused memory pages.

    Sadly, there is no option to change the delay. It is hard-coded. It does the trick though!

    The original website is gone so I might decide decompile it and realease my own version. 😛

  59. I experience this on Windows XP. FireFox is using up around 600 megabytes. It is a lot and I am wondering why? Last time it happened I only had meebo open. Ever since Firefox 3 I have been having memory issues and my computer is good enough to play games on (LOTRO, Age of Conan, World of Warcraft, etc).

    Firefox is crash happy too =[.

  60. James George says:

    Phew! I was facing the same problem on my Windows XP with 512 MB RAM and FF 3 eating up all space.. since the last 2 weeks….. whether it was opening multiple tabs (3 to 10) or going to streaming sites or just opening a single tab with any one site – yahoo / MSN / google on.

    FF3 usage hit the roof most of the time and no other apps / programs were running… My grouse with FF 3 is that it is no better than FF 2 in this area as claimed by them…

    Will try some of the options to reduce RAM usage given by the posters here…

  61. My FF3 eats memory over time. The longer I have it running, the more it eats. I’ve had mine up to a system crippling 1.9GB with just 3 tabs and 8 plug-ins. PLEASE, Firefox developers, fix Firefox or it might become Firedfox! I don’t want to have to use another browser, but it’s bringing my system to it’s knees.

  62. I have been having a horrible time with Firefox this past month. my memory usage after 15 mins browsing is 1.5 and up. if I am using a facebook app for too long I it gets really slow and have to restart the browser to finish what I am doing. the same happens in IE, but I expect that from “THEM” I may have to switch to Opera if there is not a fix for this.

  63. Abhinav K says:

    Try Firefox 3.5 RC2. It’s been tested to be the most memory efficient browser in the current scenario.

  64. I’m running Firefox 3.5 under Windows 7 with 6 GB memory. I had FF running for about 24 hours and when I checked the Task Manager FF was at about 1.2GB. Horrors!
    I might make Chrome may default Browser, although I’ll be missing some of those extensions.

  65. It seems what ever memory leak is causing this is getting worse with new updates. At first I didn’t hardly notice a difference with the initial release. And I tried 3.5 RC2 It was peaking at 1.5GB, closed all but one tab and it remained and climbed higher. This might sound odd, but after upgrading to a better memory and processor, it just seems to use as much as it possibly can, including processing power.

    So I take back my original post. The load time is worse that FF2, and much worse than Chrome, FF3 is way too bloated.

  66. Get this. Addon of Ad Blocker Plus. NOW the memory hog is gone. I have 6 tabs open and it stays @ about 100. Now that is tolerable. I am wondering when the page is autorefreshing if it calls EVERY server that is connected to that page. As a non-programmer does anyone know? It appears (to me) that the adservers connections may be it. But that still needs work if it is constantly restreaming all data on the page when autorefreshing. This is on Ubuntu. I have not looked at the XP install in while how much memory is being blocked due to I just have not fired it up in awhile.

    Also as a plus with the Ad Blocker Plus, pages load VERY fast due to no adserver connection calls.

    My 2 cents.


    • @Matt B: As a developer, it would seem to me that the underlying problem is the Flash plug-in. Almost all ads are Flash these days and while I don’t know enough about the FF plug-in architecture to speak intelligently about it I do notice that if I leave the browser idle but loaded with pages with Flash ads on them it will spin out of control — resource wise.

      It does this with Flash game sites too. Leave a Pop Cap game up for a while and come back. It’s not Pop Cap’s code that does it, but something tied to the browser plug-in architecture or the Flash plug-in itself. My gut says the former.

      • @Andy M. I understand your intent you are conveying to me. This would make utmost sense due to the install of the ad blocker plus blocks almost ALL the flash banners and ads. I also have flashblock add on due to I did notice awhile back that a flash page will keep cycling forever. I thank you for your input. I have to tell you flash is used much too heavily on the web anymore, just as elife has too many darn exclamation points. Kudos to you and continue the threads with your input.

  67. I’ve been experimenting with removing different addons and, so far, Google Toolbar seems to make the biggest difference. FF is running at 145KB right now, but I’ll have to check it after 24 hours have gone by.

  68. Well, without Google Toolbar running FF has not exceeded 185K of memory, even after running continuously for 2 days. Outlook over three days is up to 286K and 4 Chrome Processes total about 130K. I expect modules to consume much memory since my box has 6GB and Vista/Win 7 tries to make use of it all, so nothing running now is unsatisfactory.

    I have also run quite a few Youtube videos in FF and it doesn’t seem to be suffering from a memory leak now. I’ll try to add Google Toolbar back in tomorrow to confirm how the memory usage pattern differs but Google seems to be a major memory culprit.

  69. I think I win the cake ( though didn’t read all entries) at 1.1Gig of memory, going as high as 1.3gig lol.

    Continuous freezing of it, can’t do shit xD Well, I went ahead and removed half the extensions I had, some which I admit might have been memory hungry, but hot damn…

    Screenie for the heck of it lol:

    What do I win? What do I win?

  70. firefox has a poor memory management. the memory continues to grow when its idle? my one went upto 1Gb, computer was slow and firefox crashed.
    Going to switch to chrome.

  71. so maybe i’m a “power user” of firefox. I’ve got 36 tabs open. i’m at about 375MB of RAM used. That was cold booted out of the fire fox restore, because it was just recent at 1.5 GB. So how could the exact same browser windows now around 375 MB previous have taken up 1.5GB? it’s one thing i don’t like about it.. but i’d never dare 36 internet explorers open.. so it’s the best of the world we live in.

  72. bluesherpa says:

    OSX Snow Leopard, right now Firefox is using 1,011MB of ram, 39 threads, and 10% cpu… There’s one window and 4 tabs – how annoying is that. It always eventually happens and the solution is always to close all windows, restart firefox and give it another two or three days before it happens again.

  73. Firefox 3.6.3

    Time open: 36 hours
    Memory usage: 2.4 GB
    CPU: 38%

    Time open: 3 hours
    Memory usage: 418 MB
    CPU: 10%

    Switching tab, moving mouse, typing etc all slowed down to an unusable level (5 secs or more for anything to take effect). Goddamn.

  74. I've always had issues with firefox memory management. It could be that memory leakage depends on the system's hardware architecture. I'm running an AMD microprocessor and Firefox is quite slow. I've had the best speed results with Opera and Chrome but Google's browser lags a bit more yet not as much as Firefox.

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