Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Is there a memory leak in FF6.0.2?

  • 14 replies
  • 158 have this problem
  • Last reply by tinman80222

more options

Hi everybody! Immediately after start, my fresh Firefox 6.0.2 has a memory usage of around 240K. However, within an hour or two the usage reaches around 600K and the PF usage is just under 100%... :-s

All Replies (15)

more options

We will need more details about what you are doing. Memory problems are often due to combinations of sites used and software extensions.

Consider trying Firefox in Firefox's Diagnose Firefox issues using Troubleshoot Mode (but do not make changes when you see the listed options, just click on continue), and with all plugins disabled. (or all except any named plugin essential to whatever the use is).

Note you can key in about:memory, into the location bar, on recent firefox releases that gives important information about current memory usage.

See also Firefox uses too much memory or CPU resources - How to fix
the article may be being amended see also

more options

After upgrading to 6.0.2 I've had the same memory problem, along with 100% CPU usage, neither of which down. In addition, I would get various script error messages, all leading to incredibly slow computer responsiveness and Firefox and McAfee Security Center anti-virus scan freeze-ups.

Mozilla had disabled the McAfee Site Advisor plugin because of issues like these with previous versions of Firefox. I just noticed that this plugin was enabled, again, with 6.0.2.

I just disabled this plugin about an hour ago. Immediately the memory and CPU usage dropped to normal levels. System responsiveness is back to normal. No issues observed.

If you have this plugin you might want to try disabling it.

Modified by Boatnmaniac

more options

Firefox 6.0.2 + Safe Mode on a clean Win7 64 install (Q6600 processor+6 Giga Ram) AND IT STILL REACHES 1.5 GIGA of RAM...

This is since Firefox 3 for me. unbelievable.. I thought this was going to be THE browser

SHUT DOWN FIREFOX - DEVELOP A NEW BROWSER. SLOWFOX SUCKS WORSE THEN IE8. I've moved to Opera. its the most stable one for me so far (Chrome is also good, but the google tracking your stuff is pretty scary)

Modified by hk1988

more options

You tried safe mode, and possibly you tried with a clean profile or with plugins disabled. Did you try about:memory, as I mentioned in a post above ?

One possibility is that it is a problem website that you are using. By using about:memory you will get a better idea of what is eating up your memory. You may even discover an otherwise unknown problem that developers will attempt to fix. Some of the firefox developers are making concerted efforts to improve firefox in respect to memory usage, and memory reporting.

It maybe a bit geeky but some readers of this thread may be interested in some of these blogs:
more options

Definitevely there is something strange in FF6.0.2 and probably its a memory leak. W7 pro SP1 x64, (4gb Core i5 procesor) fresh install. 12 tabs open, 2 gmail acounts, 5 sap support notes and some random stuff. No plugins. FF exhauts the memory so I need to kill it with task manager.

Restart, and reload the sesion, in just 10 minutes FF takes 1GB of ram and growing. New session kill.

Restart but now in 7.0b6 x32 and it takes 246 mb of ram not growing up.

more options

Same problem - eats up memory, slows my computer to a stop. It doesn't seem to matter what site I'm on.

Main Process

Explicit Allocations 316.87 MB (100.0%) -- explicit ├──150.83 MB (47.60%) -- heap-unclassified ├──128.38 MB (40.51%) -- js │ ├──110.00 MB (34.72%) -- gc-heap │ ├───10.94 MB (03.45%) -- mjit-code │ ├────4.47 MB (01.41%) -- tjit-data │ │ ├──3.11 MB (00.98%) -- allocators-reserve │ │ └──1.37 MB (00.43%) -- (1 omitted) │ ├────2.40 MB (00.76%) -- mjit-data │ └────0.56 MB (00.18%) -- (1 omitted) ├───24.11 MB (07.61%) -- storage │ └──24.11 MB (07.61%) -- sqlite │ ├──16.54 MB (05.22%) -- places.sqlite │ │ ├──16.24 MB (05.12%) -- cache-used │ │ └───0.30 MB (00.09%) -- (2 omitted) │ ├───3.21 MB (01.01%) -- urlclassifier3.sqlite │ │ ├──3.13 MB (00.99%) -- cache-used │ │ └──0.08 MB (00.03%) -- (2 omitted) │ ├───1.61 MB (00.51%) -- zotero.sqlite │ │ └──1.61 MB (00.51%) -- (3 omitted) │ └───2.75 MB (00.87%) -- (13 omitted) ├────7.43 MB (02.34%) -- images │ ├──6.75 MB (02.13%) -- content │ │ ├──6.74 MB (02.13%) -- used │ │ │ ├──3.94 MB (01.24%) -- uncompressed │ │ │ └──2.80 MB (00.88%) -- raw │ │ └──0.01 MB (00.00%) -- (1 omitted) │ └──0.68 MB (00.21%) -- (1 omitted) └────6.12 MB (01.93%) -- layout

    ├──6.12 MB (01.93%) -- all
    └──0.00 MB (00.00%) -- (1 omitted)

Other Measurements 424.39 MB -- resident 402.12 MB -- private 345.61 MB -- heap-committed 305.36 MB -- heap-used

89.64 MB -- heap-unused
 4.63 MB -- gfx-surface-win32
 1.77 MB -- heap-dirty
 0.01 MB -- gfx-surface-image
 0.00 MB -- gfx-d2d-surfacecache
 0.00 MB -- gfx-d2d-surfacevram
 0.00 MB -- canvas-2d-pixel-bytes

Windows Vista, Up to date, lenovo thinkpad X61

more options

Hi Everyone, feel free to link between threads but I would suggest that you should start a separate question and thread for each problem. If you wish use this or another thread to track the issues.

If you have enough info to make a serious case then the procedure is to file a bug and the developers will look at the problem. I would suggest the following if you consider a memory leak is a possibility

  • try in Diagnose Firefox issues using Troubleshoot Mode <-- edit, fixed clickable link
  • disable all plugins (other than any that are involved with the problem)
  • try in the latest nightly (otherwise developers may consider the problem no longer exists)

For basic info have a look at Firefox uses too much memory or CPU resources - How to fix (the article may be subject to revision)

  • try to think what you need to do to demonstrate the problem:
    the sites used, the system in use. and the steps you take
  • if you do consider it is a memory problem then you would probably consider using about:memory to obtain information

if you can make a solid case for demonstrating a memory leak, post back again, and please be prepared to give full information.

Modified by John99

more options

The answer is to forget about this new version. I've just downgraded to 3.6.22 and there are no memory leaks. Works just as good. See OLDVERSION

more options

It is NOT from a site or from an addon. It is not even a random event. The memory grows, whatever you do. You better wake up.

more options

I have had this problem for some time, but had assumed it was down to my usage pattern - I regularly use a bulletin board / forum, and use a script to automatically open a page full of new messages at once, and invariably found that I had ever increasing memory usage despite closing them all down again.

Finally after many months I decided to look further into this, and tried looking at about:memory, which has been most instructive. Try the following :

open a fresh browser, nothing else open. open about:memory press and hold F5 to refresh it repeatedly - notice ever increasing memory usage, occasionally dropping back but not as far as it was originally. press garbage collect button, since it is understandable that it will gain some unused bits, which GC should remove - notice that memory usage does not return to original level also GC + CC doesn't help further.

So, while this may not be the cause of the leaking memory in general usage, it already seems clear that doing practically nothing is sufficient to cause memory to leak.

I've tried comparing about:memory from before and after opening a series of new posts in the forum I use and then closing them, and there are some points of note :

images are not being cleared - before opening it there was nothing showing in the output, and afterwards I had 4.39Mb (doing GC 3 times cleared them)

the "heap-unclassified" section increased by 3.5Mb too, and the "js" section increased by 7Mb, which seems to be the bulk of the increase, and doesn't seem to go away when using the garbage collection. So might actually be Javascript to blame.

Hope some of this will help with fixes, as I would prefer to keep running the latest version, rather than go back to Firefox 4, which doesn't suffer from the same problem.

more options

Hi robertdibley,

I am not sure your results are unexpected, as you are reporting single figure MB, note others report figures in hundreds of MB, but if things continue to increase you may have found a zombie compartment for instance. See

If you are sure you have a problem, or have discovered a memory leak I suggest you start a new thread, it may if you can reproduce it reliably, be worth filing a bug so that developers look at the problem.

Note also that later today Firefox Release updates to Firefox 7. You mention considering reverting to firefox 4, that can not be recommended as it is not secure, Firefox 3.6 is however still supported you could try that. As you are happy to delve into about:memory, you could also consider running comparisons by installing multiple copies of firefox, you could install firefox 3.6 and firefox 7 , 8 or 9 (but make sure you use multiple profiles). That is not a method recommended for normal users, it is considered an advanced topic, but I do not think you would find it difficult.

(I am guessing a standard install from the beta or aurora channel installs in a separate location and has a separate profile - not too sure now what was a standard or custom install on my machines now)

more options

I restarted Fx in Safe Mode at 21:39 a couple of nights ago, and with only the Safe Mode page showing, Task Manager reported Fx was using 86,480K. The following morning at 07:00, Fx was up to 170,108K.

Right now, with only a couple of tabs running for an hour or so, about:memory shows the following; Garbage Collection had essentially no effect:

Main Process

Explicit Allocations 132.99 MB (100.0%) -- explicit ├───60.99 MB (45.86%) -- heap-unclassified ├───38.68 MB (29.08%) -- js │ ├──31.00 MB (23.31%) -- gc-heap │ ├───5.05 MB (03.80%) -- mjit-code │ ├───0.96 MB (00.72%) -- tjit-data │ │ └──0.96 MB (00.72%) -- (2 omitted) │ ├───0.92 MB (00.69%) -- mjit-data │ └───0.75 MB (00.56%) -- tjit-code ├───27.06 MB (20.35%) -- storage │ └──27.06 MB (20.35%) -- sqlite │ ├──15.27 MB (11.48%) -- places.sqlite │ │ ├──14.94 MB (11.23%) -- cache-used │ │ └───0.33 MB (00.25%) -- (2 omitted) │ ├───8.16 MB (06.13%) -- urlclassifier3.sqlite │ │ ├──8.07 MB (06.07%) -- cache-used │ │ └──0.08 MB (00.06%) -- (2 omitted) │ ├───0.92 MB (00.69%) -- other │ ├───0.75 MB (00.56%) -- cookies.sqlite │ │ ├──0.73 MB (00.55%) -- cache-used │ │ └──0.01 MB (00.01%) -- (2 omitted) │ └───1.97 MB (01.48%) -- (11 omitted) ├────3.65 MB (02.74%) -- images │ ├──3.48 MB (02.62%) -- content │ │ ├──3.48 MB (02.62%) -- used │ │ │ ├──2.07 MB (01.56%) -- raw │ │ │ └──1.41 MB (01.06%) -- uncompressed │ │ └──0.00 MB (00.00%) -- (1 omitted) │ └──0.17 MB (00.12%) -- (1 omitted) └────2.62 MB (01.97%) -- layout

    ├──2.62 MB (01.97%) -- all
    └──0.00 MB (00.00%) -- (1 omitted)

Other Measurements 227.92 MB -- resident 218.80 MB -- private 137.68 MB -- heap-committed 127.19 MB -- heap-used

14.81 MB -- heap-unused
 2.80 MB -- heap-dirty
 1.58 MB -- gfx-surface-win32
 0.01 MB -- gfx-surface-image
 0.00 MB -- gfx-d2d-surfacecache
 0.00 MB -- gfx-d2d-surfacevram
 0.00 MB -- canvas-2d-pixel-bytes

Modified by PhoebeAnn

more options

Hi PhoebeAnne,

I am not to sure even your figures are too unusual. If however you wish to take this further my suggestions

  • start your own new thread
  • although the about memory info is designed to be pasted, it probably is easier to see and understand on this forum if it is also pasted as a screenshot attachment.

Maybe someone more knowledgeable will post a reply about your results, otherwise consider filing a bug yourself about the perceived problem, that should at the very least get an official comment about your results.

What is the size of available RAM installed on your computer ?

Is something in the order of 1/4 GB or less likely to be a problem on your system ?

more options

I also have this problem. It seems to be a Flash Issue and only on the ACTIVE page. You can easily see this when you have a page using flash that is the active tab and check usage, then open another tab not using any flash. While the non flash page is active CPU usage drops dramatically; even though the flash page is still playing. Downgrading seems silly, please fix this! thanks

more options

I am still having this problem in Firefox 9. Version nine! I am running in Safe Mode right now with the 9.1 FF update on my OSX Snow Leopard MacBook, and Firefox (recently restarted but with a bunch of tabs open) is using 1.15 GB of RAM. My free RAM was at over 2GB when the browser first loaded all the saved tabs, and now it's at less than 700MB free. If I leave it like this and keep using it, it will eventually eat all my memory (and I mean all - I've seen Free Memory report negative numbers.)