I love Firefox for its add-ons. I have a lot of them installed, which obviously increases memory use. But it seems that some add-ons are better than others in that department. Does anyone know a way to figure out approximately how much memory each add-on is using? Obviously, I could disable them all and try them one at a time, but I'm hoping for an easier way...

  • 1
    Not worth an answer because your mileage may vary, but personally, among my add ons, adblock plus seems to be the worst culprit speed wise. Unfortunately for me, it's the one plugin I'm least likely to get rid of.
    – Macha
    Jul 29, 2009 at 19:55
  • @Macha, maybe you could use a local proxy-based alternative if Adblock Plus really fails you? I don't know if that uses less resources, but things like glimmerblocker.org (Mac) may help for Firefox as well.
    – Arjan
    Jul 30, 2009 at 11:25
  • FYI You can use firefox profiles which allow different ad on for each for testing reasons or if you want multiple different modes for firefox. Note: The history/cookies will be different as well.
    – user3109
    Feb 11, 2010 at 12:07
  • Using memory is not a bad thing.
    – endolith
    May 18, 2012 at 0:25
  • UGH please! And yes using memory is a bad thing. There's this thing called a limit. One of the goals of every application should be to be lean and efficient, especially for something so widely, frequently, and heavily used as an internet browser.
    – Andrew
    Oct 15, 2017 at 21:05

5 Answers 5


I usually deal with Firefox memory issues by installing two different Firefox'es on my computer. The first one is the default Firefox and the other is portable Firefox.

I install all the addons I am ever going to use on the portable Firefox (FF) I install the addons which are used almost daily on the default Firefox.

This way I can use the addon just by switching over to the portable Firefox.

If this is not the solution you are looking for then try these addons

  1. AFOM - AFOM recovers Memory Leakage within the Firefox application. (Windows only)
    NOTE: This add-on has been removed by its author.

  2. CacheViewer - Allows searching and sorting memory and disk cache files.
    CacheViewer is discontinued please use CacheViewer Continued.
    EDIT: I tried it, and it shows all the files used by Firefox in the cache which eat up precious memory.

  3. bosskey - Add Boss Key, Minimize/Close to tray and memory auto cleaning to Firefox.

  4. RAMBack - RAMBack will cause Firefox to issue an internal notification to free up memory that is otherwise held for performance purposes.

  • Edit your post. Copy the url to the clipboard click on the symbol at the top of the edit window that looks like the earth with an arrow. Paste your URL into the box that pops up and hit okay. Repeat for all your url's save, put in the why did you edit this box something like "added hyperlinks to urls" Jul 29, 2009 at 21:04
  • That is very very strange... What happened to the markup?!?
    – Ivo Flipse
    Jul 30, 2009 at 11:13
  • 3
    Aha, so the number of links still depends on the original author...? Let's see what happens as soon as Rishi gets enough reputation then. (@Larry, the first sentence says "i am new so the links are not urls" because new members are not allowed to create more than 1 link.)
    – Arjan
    Jul 30, 2009 at 11:18
  • @ Arjan Thanks did not know that about that limitation. I assumed (as dangerous as that is) that he didn't know how. @Rishi +1 for fixing the links Jul 30, 2009 at 13:51
  • @Rishi : don't be a "vote beggar", if your answer is worth voting, it will get votes, that's all.
    – Gnoupi
    Jul 30, 2009 at 19:17

There's an extension called Leak Monitor that monitors add-ons for a certain type of memory leak...not exactly what you're looking for, but it's a start!

  • Yeah, not quite what I was hoping for, though it'll be good for add-on development.
    – tghw
    Jul 16, 2009 at 18:20
  • I just tried Leak Monitor and it didn't seem to solve the problem well at all. It just popped up 46 windows with cryptic messages and seized focus over and over.
    – abeger
    Feb 18, 2011 at 17:40

Only slightly less tedious:

  • Check memory usage of Firefox + all plugins.
  • Disable them all & check memory usage - difference is due to plugins.
  • Enable half a dozen (say), check memory usage.
  • If the increase is not too great repeat with the next batch.
  • If the increase is a large proportion of the usage then disable that batch and check each one individually.
  • Repeat until all plugins added.

Obviously this is probably a non starter if you have lots of plugins.

Searching for more information on those plugins might tell you something as well.

  • That's a slight improvement, but I feel like it also introduces more variables.
    – tghw
    Jul 16, 2009 at 18:01
  • Fair enough. It's up to you.
    – ChrisF
    Jul 16, 2009 at 18:03
  • It's not all about memory - the CPU usage is oftentimes the biggest hog. Aug 12, 2009 at 0:54

Mozilla released Firefox 15.0 today which has huge memory management improvements that should hugely reduce the amount of memory Firefox uses, especially after closing tabs.

You can grab it from the main download site: http://www.mozilla.org/en-US/firefox/new/

  • 1
    In all the releases Mozilla have said that it never actually seems to reduce the memory usage Jan 13, 2013 at 6:25

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