@commissar, this has been a recurring problem in Firefox even though people say it isn't. My friend who is a web designer has firefox open for days on end, and he told me he had to restart firefox twice a day or else it would lose responsiveness. He has since switched to mostly to Chrome using Firefox only when he needs to b/c for example Firefox's Firebug is still far better than its chrome counterpart.

My desktop is relatively fast so Firefox is still viable on it. But every other computer I use including my netbook use Chrome b/c Firefox performance issues such as slow cold start up are magnified several times on something humble performance wise like a netbook.

Yes, it is a recurring issue, just as people emailing (or IMing)spam links to their friends without knowing they are emailing (or IMing) spam links is a recurring issue. This is not Firefox's normal behavior. It's a problem, and it's triggered by something external, be it an add-on, a virus, spyware, antivirus software, firewall or whatever. So you need to diagnose it before you fix it. Do this:

1. run Firefox in safe-mode to disable all extensions, themes and plugins. If this fixes your issues, be them with RAM or CPU usage, then you know it's a problem with plugins, themes or extensions. Proceed to number 2. If safe-mode doesn't fix the issues, then read bellow, after this list;
2. update all extensions, themes and plugins in your Firefox. If this doesn't solve the issues, proceed to the following number;
3. disable all extensions, themes and plugins in your Firefox (not running safe-mode). Being certain that, as in safe-mode, the problems you're having have gone away, enable one plugin at a time. You should be certain that you WANT that plugin to be enabled, so keep your overall number of plugins as low as possible. When you encounter the problems, you know you've found a problematic plugin, so disable it for good. Keep enabling all plugins (except problematic ones) until you've gone through them all.
4. enable one extension at a time. Again, be certain that you WANT that extension to be enabled, so keep your overall number of extensions as low as possible. Also, try the theme you want to have installed so see if that is what's causing the problem. When you encounter the problems, you know you've found a problematic extension/theme, so disable it for good. Keep enabling all your extensions (except problematic ones) until you've gone through them all;
5. you're done! You've fixed your problems with problematic add-ons. If you want to keep using those problematic add-ons, please contant their author for support.

Ok, if disabling all extensions and plugins through safe-mode didn't work to bring Firefox's CPU and RAM usage to good levels, then you have different issue. The most likely scenario is that you have a third party software running on your computer that is messing with Firefox. Do as follows:

1. try reinstalling Firefox. No data will be lost. You can get the latest version for free at getfirefox.com. If that doesn't fix the problem, proceed;
2. do a virus/malware check on your computer. If this doesn't fix it, proceed;
3. disable all software running in the background that you don't want to have running in the background (in windows, this is done by pressing WINDOWS+R in your keyboard, typing "msconfig" (without the commas) and pressing enter. Now, under the "Startup" tab, you can uncheck the software you don't want, and reboot your system for changes to take effect. If you're unsure of what software you want running, ask someone with more experience). If this doesn't fix your issues with Firefox, proceed;
4. check your firewall/antivirus/security suite for enabled functions/features that you don't want and/or may be conflicting with Firefox. You'll find that these features are most likely tied to Internet Security features, such as link scanners or URL checkers and the like. If you're not sure they are conflicting with Firefox, simply try to disable them to see whether or not that's true. As long as you don't browse the web with your antivirus completely off and your firewall completely turned off, there should be no problems. If this doesn't solve the issues, proceed to the following number;
5. check your operating system security options, mainly advanced options that are not configured by default. While it's very unlikely that this may be the cause of the problem (after all, it's the last item on the list), it's remotely possible. If this doesn't work, proceed to the following point;
6. update your modem/router software. There have been some reports that some modem/router software may cause Firefox and other browsers to loose performance and/or stability. If updating doesn't fix your issue, try other versions of the software, if possible. If you need support with this, contact your modem/router manufacturer. If this doesn't help, proceed;
7. clean up your OS registry, using appropriate software. Make sure you've followed my instructions correctly, but if this all doesn't work, create a new Firefox profile (this can be temporary, of course) and see if the issues persist. Report here the results, so we can help you further.

Mozilla won't do shit to fix the memory leak, stop acting like they will. Firefox has been bugged with it since birth, they aren't skilled enough to know how to fix it or they leave it in to slow down everyone's PC because they are bastards, either way Mozilla won't fix the memory leak. It's like their signature flaw or something.

"Mozilla won't do shit to fix the memory leak, stop acting like they will. Firefox has been bugged with it since birth, they aren't skilled enough to know how to fix it or they leave it in to slow down everyone's PC because they are bastards, either way Mozilla won't fix the memory leak. It's like their signature flaw or something." Yeah, Firefox really doesn't have any sort of memory leak like the one people are describing it. This is caused by external factors, clearly, as it doesn't affect most of the users. Please read the post above yours, and hopefully that will help you fix it. If it doesn't, tell me the results of the last point in the second list.

This is something I don't understand.

If the generic response is that it is not FireFox but something on the PC than how come changing to a different browser fixes the problem of memory Leaks? (i.e. they don;t suffer the same problem?)

I mean simply using another browser means we do not suffer any memory leaks... so what gives? Why is FireFox so different or so temperamental in regards to what else is on someones PC?

Also how come the most prominent "chrome" errors that keep stalling page load-ups etc doesn't happen on any other browser? I mean that bug is so annoying and pops up all the time no matter what extensions are or are not installed.

Too many excuses for my liking. We all know there is something wrong with FireFox so I dunno why the developers don't simply acknowledge it.

Fix it so it is not so temperamental and is more solid on our system like other browsers are. It should not be so sensitive to its environment. The others prove not to be so.

Ok so after a few more weeks of testing, I return...

I disabled Shockwave on Fx - this was huge. I can no longer display anything with Flash (obviously) but the stability has increased an order of magnitude.

I am able to run about 30 tabs fairly well (memory usage is still very high, but with 24GB of RAM I don't care), and most importantly, the browser doesn't lock up or get sluggish after a few days of being open to the same tabs.

That said, running more tabs immediately starts to throw Fx for a loop, and the responsiveness dips. As I've noted from the first post I ever made here, My problem is perhaps different from the generalized one people seem to be having - I want an "industrial" browser that can run 300 tabs if I want it to (and I do) so long as I can support the memory requirement. NO BROWSER I've used can do this well at this stage (so I run 8 different browsers at once...)

Fx however, is definitely still the most troublesome - it does occasionally crash, though as I've said with FLASH turned OFF, this is mostly a fleeting occurrence. For the most part, I'm currently OK with Fx's performance, though Opera is much faster, Chrome and Maxthon much more stable, Flock amazing for video and Flash by comparison, IE deals with Proxies better and Safari rarely crashes even under heavy load.

Clearly, I think Fx should be able to run Flash stably (which it can't), but even aside from that, I feel like Fx should BE that industrial browser I'm talking about, I feel like it should aspire to be something unique, the best.

Yes, the claims about 3rd party software being involved are legitimate, and we cannot base assessments on anecdotes. Still, the burden of proof here rests not on the users (I mean, is Windows Vista considered conflicting 3rd party software with Firefox?) but with the browser.

We all love Firefox I tend to believe - why else would anyone bother to argue about the differential between browsers, none of which cost anything to use? We're not here for flame wars, so please keep the rhetoric civil.

I think that with the massive number of complaints, all sounding eerily similar, the weight of evidence is solidly against Firefox at this point. The only users I can find who report no problems, and I work at NASA, where I assure you we've got some very intense users, are the ones who basically open and close the browser in a single setting, and open 10 tabs at most on an instance.

That is obviously not what I've been talking about RE performance and memory leaking. And of course, if nothing else, Flash should run in Fx, period. The fact that I have to use Flock (Mozilla platform!) to see Flash is silly.

I'm not a dev, and won't even bother to claim any knowledge of that realm - but I know this: all of these users are not incompetent software users - SOMETHING, I don't what, but something, is fishy with the 'Fox.

I do hope the next release proves more promising.

I must admit when using Firefox in 64bit I see more stability too.

I assumed it was due to the extra memory resources of a 64bit software.

Perhaps though it is because Flash is not being used. Unfortunately this is also the reason why I can't use a 64bit version of Firefox.

I'm now testing 4.01 to see if anything has improved. Too soon to tell (just had it for last 20mins).

@ Paul

"If the generic response is that it is not FireFox but something on the PC than how come changing to a different browser fixes the problem of memory Leaks?" Because it's probably something with an extension or theme, and those are for Firefox only. Or maybe with a plugin for Firefox. Flash for Firefox is not the same as Flash for Internet Explorer, for example. Or maybe it's malware that is targeted at Firefox and that is not working "correctly"... I really don't know, unless you tell me.

"I dunno why the developers don't simply acknowledge it" Firefox is developed by "we all". It's open source, the bug list is open, accessible and editable at bugzilla. That said, most of the contributors here at Firefox support aren't Firefox developers.

@ TheCommissar What I don't understand is why you don't follow advice and try to work with us to find a fix... Please try running Firefox in safe mode, disable all add-ons at safe mode startup, then see if the issues are there. If they're not, please disable all add-ons (that's extensions, themes and plugins) on normal mode and make sure the issues are gone. Then enable one at a time (enabling half of them each time and going on, narrowing down the search does it) until you find the problematic add-on. If that (safe mode) doesn't work, please see this post and follow the second list. If it doesn't help, please answer the last point.

@Morbus I'm not sure how you forgot... but I DID follow all those procedures, and in fact used a new computer (a laptop) in one instance to do so, some weeks ago. The only thing I found was Shockwave, and I disabled it to good gain.

As I said, at the moment I'm ok with Firefox's performance, even if its a bit less stable than some of the others.

Enabling Flash is simply not doable, and it results rapidly in an unusable browser no matter which machine I have tested on with or without addons, etc. But I'm ok just using another browser for that.

I've spent way too much time trying to deal with what are quite obviously, despite your efforts to fix them Morbus, issues with the underlying software. You are using the vast majority of users as evidence of obviousness: if there were a true problem a large contingent amongst millions of users would have noticed it by now.

But a large group have. Is it possible that they're all running incompatibilities? Sure. As I mentioned merely running Windows Vista meant you were essentially running clashing 3rd party software. Furthermore, as I've noted, for the majority of users Firefox DOES operate well - light browsing (a dozen tabs), and relatively frequent restarts produces few issues with Firefox, as I have observed.

That doesn't mean however, that these other people should have to "fix" the browser themselves. Especially when the other browsers don't seem to immediately possess these kinds of issues (and as I've said many times now, none of them do what I really want them too).

I cannot, and won't, defend software that the user needs to troubleshoot like this - if addons are just hacks that work for some configs, if tabs cause memory leaks when left open for too long, and if the browser crashes after long periods of time and requires restarting FOR ANY REASON under normal operating conditions, then it's not performing to spec.

Chalking up these issues essentially to user error (which I would consider software incompatibility for instance) is just not sufficient defense. IF incompatibilities are causing these problems, then they should be resolved ON the software side.

Sorry, TheCommissar, lost track of the usernames... I'm really sorry.

In any case, this is an unusual issue and I don't know how to fix it, it seems. I'm really sorry that I can't be of help. Maybe the crash reports would tell us something, but I'm not sure I can read much into them...

This thread seems to have been hijacked. Kerem, are you still experiencing the problem?

@Morbus,

No problem - I see what happened now - someone's been using the same username as me... which is really confusing; no idea why...

And yes, I know I have a slightly different issue - I hope the day of the super-browser is soon upon us.

I experience this same issues as well and I get over a gig of memory use.

I run 2 windows of Fx with around 10 tabs each.

If the Flash plugin is a cause for this problem, obviously this needs to get fixed as it's been a reported problem since 3.6.3 and I am now on 3.6.7.

Yes, I have this problem too, and see this problem on other computers in this house. They all run Win7 64-bit, Firefox 3.6.8.

The memory usage really isn't the problem on this computer at least. It is huge at times (800MB or more), but that's tolerable. The problem for me is that it makes Firefox periodically pause. It's short, but can affect scrolling, typing, or watching videos. Closing individual windows helps nothing. Only closing the entire program out frees the memory.

The memory usage I'm reporting is on the Firefox process itself. The plugin container process uses about 50MB of memory on average. Note that the memory that is used is "private bytes," as reported by Process Explorer, meaning physical RAM. On the other machine I have with only 2GB of memory, this can cause the system to be exceptionally slow. This machine here has 12GB, no pagefile, and yet still suffers from the pauses in Firefox, so it's not a paging issue.

To see if there were problems with the cache, I installed a cache monitor. It reports the memory usage (max of 32MB), and disk usage (up to 512MB). Rarely is more than 16MB of the memory cache used, and only about 140MB of the disk is used. This is global across all windows.

I'm running some tests to see if the add-ons are the problem. From past tests, I believe it still had problems when I disabled the add-ons from the addon list. I'll verify this later. This time I'm running with no plugin support whatsoever from safemode (everything else enabled). I'll see how it goes.

Here are the results of my experiment. I started with about 4 windows open (can't tell exactly from the screenshot): one with a single page (i.e. 1 tab), one with 5 tabs, and the other two windows with with at least 2 tabs. At the end of the experiment I had two windows open: the 5-tab window, and the single-tab page. The 5-tab page was used slightly (only one tab was actually modified); the single-tabbed window was left untouched and has no history; most of the web work was done with other browser windows. No tabs of either of these two browser windows had any "active" content that would update the page dynamically or retrieve data from remote sources, nor any scripts that run in the background eating memory. I closed the other windows prior to taking the memory survey.

After nine (9) days, with all add-ons disabled via the Safe Mode settings, my memory consumption (as metered via Process Explorer) went from 358MB Virtual Size, 187MB Private Bytes, and 209MB Working Set to 914MB Virtual Size, 476MB Private Bytes, and 501MB Working Set. Restarting the browser (File -> Exit), and opening up the same set of windows at the end of the experiment, plus another to type this message yields 257MB Virtual Size, 80MB Private Bytes, and 105MB Working Set.

Something in this browser is eating memory and not releasing it, not related to the add-ons. The lack of add-ons did help with memory consumption, however, and the browser experience was not degraded as quickly as if the add-ons were present. I can usually pull 800MB-1.2GB within a day or a few days with add-ons enabled, which causes periodic pausing; it took six to nine days before memory consumption reached the 500MB level without add-ons enabled. Note that this system does not have a pagefile, so disk accessing for memory allocation would not be a cause of the stuttering.

The memory leak also does not seem to be caused by the browser simply being open. I've left the browser on for a few days before and it does not simply "leak" over time. This leads me to believe that the leak has to do with caching, especially since add-ons such a Flash will permit downloading heavier amounts of data. I've heard that Firefox uses a tree-like page caching system so that back and forward page traversal is sped up. Maybe memory is being lost in the process.

Whatever the problem, please look into this. The problem is real, and it's annoying. Running this browser without add-ons is pretty much the same as switching to a browser like Chrome, which does not suffer these memory leaks. Switching may even be a permanent solution, should this not get patched.

No change in this bug for version 3.6.8.

Try the firefox addon "Memory fox" and see if it helps you to keep more pages open. Firefox does seem to have problems reclaiming memory over long periods of time when many tabs are open but this addon has lowered my memory usage quite a bit. It has gone from 400-500 mb down to 100-200 mb even with approx. 30 addons enabled. I am not sure if there is a performance hit or not, if there is I have not noticed it.

I wish I could find that plugin. It appears the author has disappeared, and so has any reference to Memory Fox on Mozilla's add-on page. Even typing in one of the URLs I saw of Memory Fox in a screenshot showed the blog page has disappeared. So sad, because from the posts related to it, it seems it might even work.

I still find it pathetic that a plugin needs to be written to fix a fundamental dysfunction of this browser.

I'm trying a copy of Memory Fox the developer has linked to in the Mozilla forums. Perhaps this will fix some of the issues. For reference, it can be found by searching for "[Ext] Memory Fox version 3.2" on your favorite search engine.

I searched for "Memory Fox" on Google and the first hit, excluding ad pages, was memory fox v4.8 at https://addons.mozilla.org/en-US/firefox/addon/53880/. The homepage for the addon is http://www.browsermemory.com/. Just make sure you stop or deactivate Memory Fox before upgrading or it might become unstable.