Whenever I leave Firefox open for more than a day or so, the memory usage always climbs up to illustrious heights. I have plenty memory (48GB) on my 64 bit machine, but for a 32 bit process this is useless anyway.

When usage becomes above 1GB Firefox becomes slower (it takes whiles before it shows typed characters, it may take seconds before it reacts to focus or tab change etc).

  • Is it possible to have Firefox use less memory?
  • Would that than limit usage or performance?
  • Isn't it a problem for 32-bit processes to reach above the 2GB limit?

Using most recent version of FF 6, but this issue was around for all versions I can remember.

enter image description here


PS (edit): just tried once more to kill all but a few tabs, and this actually increased the memory usage up to 2.5GB. Clicking "minimize memory usage" on about:memory doesn't help even a bit.

  • Does disabling all your addons make a difference? – Shinrai Sep 27 '11 at 15:20
  • @Shinrai: possibly, but since plugin-container.exe only uses about 80MB at this moment, I figured that the plugins were not making the difference. Or is that a wrong assumption? – Abel Sep 27 '11 at 15:28
  • 1
    @Abel - First rule of problem solving, eliminate possible reasons for the problem itself, come back when you have eliminated the possible reason. – Ramhound Sep 27 '11 at 15:29
  • 3
    @Abel: plugin-container.exe is only for hosting NPAPI plugins, like Flash, Java, Silverlight, etc. Add-ons are hosted by the firefox.exe process itself, and it sounds like either something is wrong with your profile or you have a buggy add-on. It's rare now, but I've seen cases where creating a new profile was needed to clear up crashes or other weird behavior. That said, most unbounded memory leaks in Firefox are the result of bugs in 3rd party code, either an add-on or a plugin. – afrazier Sep 27 '11 at 19:24
  • 1
    Possible duplicate of Is there a way to reduce the memory usage of Firefox? – YetAnotherRandomUser Feb 28 '18 at 20:39

I have been running into this problem in Firefox for years. I use SessionManager to be able to recover after I forcibly crash Firefox and restart it, because I haven't found a reliable way to prevent Firefox from gorging on memory. There are plenty of extensions that purport to plug the memory leaks, though they usually only last for so long before Mozilla changes things to break them.

Today, while being irate at this issue and looking around SuperUser, I found an article that seemed to have something useful. 20 minutes in, and memory usage has stayed around 500mb, and it was ~3GB before I tried the setting. I did have to crash and restore Firefox though. I think the magic came from one or all of these settings:

Type “about:config” in your browser bar and adjust the following preferences (by double clicking on them) to free up some additional memory:

browser.cache.memory.capacity (set to 0)
browser.cache.memory.enable (set to false)
browser.sessionhistory.max_total_viewers (set to 0)
browser.tabs.animate (disable)

There are also a smattering of other settings on that article that seem useful.

| improve this answer | |
  • I'm going to accept this as a much better answer than my own, even though it's many years after I posted it. Tx – Abel Mar 1 '18 at 15:26

•Isn't it a problem for 32-bit processes to reach above the 2GB limit?

The limit for a 32-bit process is actually 3GB( 4GB on a x64 operating system ). Are you sure you have 48GB of memory that seems really high if your getting a performances issues with a process taking only 1GB of memory.

Have you tried running the 64-bit version of Firefox?

How many tabs do have open exactly? What is the contents of those tabs? What in the world are you doing that allows Firefox to use 2GB of memory in the first place?

| improve this answer | |
  • Yes, I do have that amount of memory, but that's required for other apps than Firefox. I realize it is rather high. I haven't tried 64 bit Firefox, is there an official release already? I wished I had the answers to your last question, but all I do is google, SX sites, using Jira and some news sites. Pretty boring stuff, actually. At this moment I came from 30 tabs to 12, still 2.3GB. – Abel Sep 27 '11 at 15:30

You might try upgrading to a later version of Firefox. FF7 is supposed to be released today [1], so you could start there—I think it was supposed to bring memory improvements. If that doesn't work, you could try upgrading to either of the Beta or Aurora channels. I'm currently on Aurora, and it's worked very well for me. Barring that, I guess I'd see if anyone on support.mozilla.org can help you.

EDIT: Firefox 7 has been released now, so you should just need to update Firefox to try it out.

| improve this answer | |
  • So far this issue has been bogging me for all version of Firefox ever since 2.0. But I'll try it regardless, tx for the tip. – Abel Sep 29 '11 at 11:49
  • I started with FF4, and versions 7 and 8 really improved my memory usage. I think it was on version 7 that I finally switched back from Chrome. – zpletan Sep 29 '11 at 11:53
  • Also worth noting that 8 was supposed to move to beta and 9 to Aurora a few days ago—not sure why that hasn't happened yet, but it should soon. – zpletan Sep 29 '11 at 11:55

In my case, the PDF plugin and the flash plugin was causing the memory troubles. Still don't know why they use memory of firefox.exe, and not from plugin-container.exe, but browsing for 24 hours with on average 40 tabs, but without many animations and youtube videos, kept the memory to a "reasonable" 800MB.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.