I have Firefox 4 running on Mac OS X. Pretty vanilla set up, with AdBlock Plus as the only extension and plugins limited to the likes of Silverlight, Flash and Quicktime. I love how quickly FF4 launches, but find that just regular everyday browsing causes it to balloon in size, with the Mac Activity Monitor frequently reporting it using over a Gig of free memory.

FF3 had some minor memory leak problems, but I understand a lot of that (likely) came from poorly written web pages. This, in comparison, is ridiculous. The browser is borderline unusable for anyone who doesn't have 4G of memory.

I was noticing the same issue where Firefox was using 1.5+GB of RAM after a half of a day of browsing. I went and checked for updates to any installed plugins and sure enough there was one for flip4mac (for playing certain Windows video formats) and Silverlight. I installed them and now it looks like Firefox is a little more under control only consuming 760MB at the moment after a couple of hours of browsing.

Give it a try -> http://www.mozilla.com/en-US/plugincheck/

Only problem is that this is a semi-fix for the Mac. Which I'm glad for since I use a Mac at home. The problem is that the fix won't resolve the windows variant of Firefox 4.

Firefox has had memory usage problems for years. Based on the fact that version after version have been released with no significant improvement I have come to the conclusion that it's intentional and yet another sign of collusion between software authors and hardware manufacturers to force people to buy newer faster computers and more more more memory.

Ok, the Mac Version is worse... and I never thought I'd live to say it. I have no extensions except one, and only the necessary plugins none beta, and none that are not compatible with Firefox 4... I don't have any plugins that depend on much resources at all period.

Two hours of browsing and the browser freezes up. This is getting unbearable. I'll be switching to Chrome by the week's end if this isn't resolved.

Huge leak here after a day of browsing and then closing most of my tabs, just leaving 3 open, none with anything major, and firefox 4 was using 1.7 Gigs of RAM!!! WTF?!? I've often noticed firefox taking up a gig of RAM but never this high. I even closed firefox and it would release the RAM I had to manually close the process from the task manager. Firefox, I love you but if this doesn't get fixed soon I'm afraid we are getting a divorce...

I have the same problem. It happens at random times and forces me to use Chrome. I'm running Firefox 4, Windows 7 and a computer with 4 G of ram.

Yes, a very serious memory leak. In casual analysis on my system it seems to be invoked by dynamic image management. I can make it happen in a matter of seconds by going to Google Maps, selecting satellite views, and scrolling around. Then it starts going through memory like a tree shredder and mem page swapping goes nuts. The fastest and sometimes only way out is to power down and up.

I find it hard to believe this product made it past even the most basic QA, much less having been in beta for a year. It's broken in an embarrassingly major way. I "downgraded" (hah!) to 3.6.17 and restored at least my own little world to normal.

Huuuuge FF fan; been using it since 1.5, i'm a web developer and i love it.. but this has got to stop. Browsing a little, closing all tabs but the one i'm working on and still get 1 gig ram usage with FF (out of my total 4). Add-ons? only 12, but 4 for development. My IE colleague is laughing at me, I am ashamed. I'm writing this from Opera.

I have a i7 980Extreme with 12GB RAM and Firefox eats up 1.5GB in a few hours of surfing the web. I start noticing the browser runs slow with delays hoovering over buttons and what not. This SUCKS big time has the ff team even addressed this as an issue or wtf is up?

To answer your question, no they have not. This has been a posted issue for over a month and none of FF's people have responded.

This is actually quite disheartening. I have been using FF before it hit mainstream... pre version 1.0... and now I am really thinking about leaving the FF browser until this is fixed.

I did it before, and I will do it again. As we are speaking I am using a mix of Safari and Chrome to browse. I'd like to make FF my browser again, but not until this bug has been fixed.

I have had this problem with varying intensity with all versions of FF from v2ish to now 4.0.1. Typically it uses 150-350mb sometime 512 outof my 1024MB of RAM

on another parallel question someone posted this : Possible Solution: I had the same occurring issue with my firefox too. I found that disabling the page file in windows fixed up my memory leak. It seems firefox stays in memory and takes space on your OS's pagefile, causing reports of doubled memory in the task manager.

Is this true I would like to try it but can I disable the page file for FF exclusively and keep page file for OS and other programs?

XP SP3, 1024MB ram, 3.2GHz petuim

Ok, I know the FF Developers follow these forums, post to these forums, and use these forums. Why has none of you commented or pointed out that this is an issue, and will be fixed, or is a known issue and you are working on getting it resolved?

There are over450 people within a month's time who have had the same issues as me with Firefox 4 and 4.0.1, I am sure with each post that occurs here the number will increase exponentially.

I have regretfully stopped using Firefox 4, I can't handle the slowdowns, or the memory hemorrhage that Firefox 4 has.

I as well as those people who have commented, or posted they have the same issue, I am sure would like to know we are not being ignored.

Are we?

I noticed 1.2GB of ram taken up on Win7 x64 & 4gb of ram config, version 4.0.1, while just a few tabs (a matter of 3-4) were open. To add to that, lag was inbearable, as typing inside taxt-area simply dealt no answer whatsoever until a few seconds later all the text I had written got to screen all at the same time. Closing the program, it slowly began freeing up its memory toll up to 800MB, according to task manager, then finally closed. I am working on a re-opened session, and this is about the max tabs I've been using (5), and the memory taken is now 574MB, no matter what I do I find it higher at every wake from hibernation.

I have 4 GB of RAM and it doesn't even work with that. It will over the course of the day balloon oversize until eventually I have no memory left. At that point everything you do in browser has a delay and the only way to rectify it is to Quit and Re-open the Browser.

The part that bugs me, is that this has been going on since Beta, since early Beta in fact and it's not being address by anyone at Mozilla. I love their products, but they have to realize that this kind of memory leak is pushing people away and is completely unacceptable.

Just go to NPR.ORG and play a program using their streaming player and you'll see firefox.exe memory usage climb w/o bound until Windows locks up. I experienced this using FF 4.01 on both Win XP 32 as well as WIN 7 32. I seems to be page dependent as I have seen it happen on a static page as well although much more intermittently.

I also have a NetBurner embedded web server that uses AJAX callbacks via a Javascript timer. This application also leaks about 30kB per second (the rate of my callback) so I assume that there is a leak in the Javascript engine or in the basic HTTP packet memory release?

I'm going back to 3.17. It has half the memory footprint of 4.1, and doesn't leak under these circumstances. 4.1 should be withdrawn until it's fixed!!!

This is a ridiculous problem, and it seems to get worse with each new release. At least with 3.6 there were extensions to help keep it under control, but they aren't compatible with the new version. I don't feel like uninstalling and downgrading, so looks like I have to use another browser till this is fixed. To think IE is now preferable to FF. Unbelievable. Please, developers, FIX THIS!

Same problem here. At first I thought that it could be an add-on or plugin .. but even with all of them disabled the same thing happens. After a few hours of use the Firefox process grows to 1.6 GB and then the whole browser gets lagged. Using Firefox 4.0.1 with all add-ons disabled .. on windows 7 64.

With all the talk and marketing about how much better Firefox 4 was going to be, combined with their faster release process, I was hoping that the Mozilla team had finally worked out their development, testing, and QA. I guess not :(

This is a problem still, and honestly I am using Chrome now. I don't dare use IE, too many security issues in itself. I'd rather use FF, but I can't afford the slowdowns any more.

I found this page useful: http://support.mozilla.com/en-US/kb/Firefox%20consumes%20a%20lot%20of%20CPU%20resources?s=memory+needs&as=s

In particular I disabled the AVG Security Toolbar, and it sems to have stabilized the memory useage. Previously with Firefox4.0.1 my system was eating memory - much worse than 3.6.17 (which was giving some problem anyway....). My machine is an old one with only 500Mb RAM, running Windows XP