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memoryFoxHeadDo you use Firefox? Most of our readers do and we all know that 10 open tabs can be highly problematic for our system memory. There have been times I have seen my Firefox get close to 1.5 gigs of memory. That is just unacceptable!

So what do you do? Do you stop using Firefox? Absolutely not! Will you use Internet Explorer? It is just as big of a resource hog and it causes system crashes as well (well it depends on what version you are using).

I have found a much needed extension to control and reduce the memory usage in Firefox called Memory Fox. You can grab the installer over here.

So to start, I took a look at my 4 open tabs in Firefox. They are using 256 Megs of memory. No big deal right. But a few hours from now that can balloon up to 4 times what it is. You can see my task manager open below with the Firefox process at the top hogging up my resources.

reduce memory usage firefox


And that is on a good day! What about my Vista machine at home that ONLY runs Firefox? Take a look at the 1.4 gigs of used memory below. Sheeesh! Apps should not be allowed to do that!!

reduce memory usage firefox

So head on over and install Memory Fox from the above link. You will need to check the checkbox next to the big green button that says Let me install this experimental add on. Once you click this checkbox you will be able to click on the big green button and download the extension.

decrease memory use in firefox

You will be prompted to restart your browser as usual. When your browser comes back up go to the tools menu and you will see a new entry towards the bottom for Memory Fox. You will have one option to activate Memory Fox or deactivate Memory Fox. I think those options are pretty self explanatory right?

So what did I do? I think I did what any other IT dude would do – I opened 25 tabs in FireFox with a whopping 1.2 gigabytes of memory in use right off the bat. Then I activated Memory Fox like so”¦


and presto changeo – memory usage in Firefox dropped down to under 10 megs. It did jump back up to around 90 megs but the process from Memory Fox kicked in and dropped it back down to about 40 megs. And this is where we have been all day. I have not seen any other negative effects and it has indeed speeded up my web browsing.  Other tasks on my computer also have more resources due to FireFox being tamed.


For those of you wondering what is behind this magic let us look to the author’s website:

Memory Fox focuses on two ( 2 ) types of memory usage and with flushing for memory recovery. When resource requirements ( Stack and Heap ) have been reached, according to the user’s preset option settings, the memory will be flushed and recovered from Fragmented Orphaned Ram memories.

Below are the two types supported for recovery.

I was unable to find my preset option but I know that it is 50 megs because that is when Memory Fox kicks in and reduces the memory utilization. All in all this is an amazing free utility and should be built into Firefox for sure!

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  1. Bill Minton
    February 23, 2010 at 9:57 am

    Yeah, I just uploaded a copy to MediaFire -{1.09}.xpi

    It isn't going to stop running on your machine, there's no "sync" setup between your addons & the website.

  2. Unionhawk
    February 23, 2010 at 5:52 am

    MemoryFox is gone. Dead. No longer in existence.

    • Karl Gechlik
      February 23, 2010 at 9:42 am

      Strange it is still running on my machine. Anyone know where you can download it?

  3. poch
    January 21, 2010 at 4:23 am

    Everytime I use Firefox, my laptop frequently overheats or FF crashes. I use Google and Opera at the same time yet that doesn't happen. Could the reason be FF memory usage?

  4. Rodolfo
    January 18, 2010 at 9:30 pm

    this firefox add on really works anyone getting error in downloading its latest version MemoryFox 1.3,all you need to do is to have an account in Mozilla official websites there you get it without a hazzle...Thanks to this site...

  5. JK III
    January 3, 2010 at 9:47 am

    Just a question out of curiosity, what happens when your computer uses up "all" of your ram? I guess it crashes, but anything else?

  6. Kitarist
    December 18, 2009 at 3:45 am

    I only have a gig of ram and my FF was using like 300k of resources everytime i was running it so my whole system ran really slow. Now that i have installed and enable memory fox the usage is only around 75k 80k average and everything runs like butter now!!!

    Just great!!!

  7. raj
    December 17, 2009 at 3:35 pm

    How is this better or different than SQL-lite Manager addon?

    (PS: It would be great if Authors can compare to other existing, Non-Experimental addons.)

    Thank you for the article.

  8. Ron M Kolman
    December 17, 2009 at 2:11 pm

    INCREDIBLE. Cut FF's usage by half!
    Thanks. Love it.

  9. AussieRodney
    December 16, 2009 at 11:15 pm

    Using it. Loving it.

  10. Alessandro
    December 16, 2009 at 1:13 am

    In task manager there are two processes firefox

  11. makbruno
    December 15, 2009 at 10:01 pm

    Thank you all for sharing alternate links.

  12. Quickroute
    December 15, 2009 at 3:56 pm

    FYI - You need to register and sign in with Mozilla or it won't install properly i.e. gives an error msg about invalid package

  13. A
    December 15, 2009 at 3:14 pm

    1.5 giga, i mean, really?? If I open 40 youtube videos in Opera I get around 900 mega. Yes, it takes forever to free the memory afterwards, so I usually kill the process. Still. I have never ever seen 1.5 giga of memory used.

  14. Sheel
    December 15, 2009 at 2:27 pm

    I have a Vista running on HP machine & presently I am facing an issue with memory shooting up to 100% and fan start making noise. When I see the task manager I can see Firefox is eating all the memory. I will try this software (memory fox) today and see if it helps or not. anyways thanks for posting such a great info.

  15. Teknojunkie
    December 15, 2009 at 12:53 pm

    The only way it appears to work is to remove the "?confirmed" from the end of the URL. It will make you sign into the site, presumably due to the experimental classification of the plugin. I was able to successfully install it by doing this.

    Good luck!

  16. Xtreme
    December 15, 2009 at 12:39 pm

    Here is the updated version for firefox v3.5 â–¬>

  17. Karl L. Gechlik
    December 15, 2009 at 12:07 pm

    Wow! I do not know what happened between yesterday and today but I still see the version I used 1.01 available from this link

    Try that and let us know how it works out.

    Talk about bad timing!

    • roger
      December 15, 2009 at 2:56 pm

      I've just followed your link to version 1.01, downloaded it and with 25 tabs open it reduced my memory usage by 100Mb approx. Thank you, Karl.
      Best wishes to all at MUO and enjoy the holidays.

    • Paul-G
      December 15, 2009 at 7:06 pm

      Thanks Karl.

      I did not need to remove "Confirmed" for the D/L to work and the simpler Options page implies V1.01.

      NOTE for anyone else 'downgrading' - I did see mention of "Dissable befor Un-Install" on a page somewhere so I did that before clicking on the 1.01 link. It may not be required but might help.

  18. Paul-G
    December 15, 2009 at 11:20 am

    The comments on the Add-On page repeatedly mention that the settings are a bit geeky. I agree even though I am considered to be a geek by my friends.

    It now downloads and installs OK. Unfortunately I don't think it is working as I am getting pop-up info boxes every few seconds saying "Memory Release Failed".

    I would suggest waiting for release 1.04

    • Dirk
      December 27, 2009 at 9:12 am

      I had the periodic "Memory Release Failed" pop-up and solved it by setting atom.exe to trusted in Online armor.

  19. Bill Minton
    December 15, 2009 at 11:16 am

    I had issues getting it as well, but finally got it. Here's a link to it -

  20. kaztik
    December 15, 2009 at 11:11 am

    i was getting error 207 too
    But strangely when i signed in to the addons.mozilla site the installtion worked the first time i tried ....

    • Christopher Proudlove
      December 15, 2009 at 11:20 am


  21. Christopher Proudlove
    December 15, 2009 at 11:08 am

    Yeah ... let me know when it's fixed.

  22. Shadow
    December 15, 2009 at 10:57 am

    No problem to download and install this now. My memory usage was instantly redused 10 times. Amazing :)

    Downloaded this one:

  23. JK III
    December 15, 2009 at 10:54 am

    I dont want to nitpick, but I have got currently 10 tabs opened, and my FF (3.5.2) is using 165 MB memory, on XP. The maximum I have seen it go is around 300 MB, and that is when i have 25+ tabs opened.

    And yeah one thing, just after starting firefox (only after starting it, not during usage) I run Cleanmem. Maybe that has something to do with less memory usage. But even without cleanmem, it does not go as high as as yours does.

    • june
      December 16, 2009 at 3:51 pm

      I've even gotten to the point of having 200+ tabs open (I was mass-browsing photography portfolios) and it hit about 600Mb. And I dont even use any programs that lessen the memory usage. Right now I'm thinking a computer must be severely outdated if it begins to lag at only 6 tabs open.

  24. Abhilash
    December 15, 2009 at 10:39 am

    Unable to install as I keep getting "Not a valid pakage install - 207".

    • Rodolfo
      January 18, 2010 at 9:25 pm

      you need to have an account to download the MemoryFox latest version i did to successfully downloaded it & installed it on my firefox which i find did really owrks what ws said here...good luck on your next attempt to have it...

  25. James
    December 15, 2009 at 10:11 am

    Same issue at the above. Can't offer any help... just posting so that I can get the auto-update when someone posts a solution.

  26. CrazyGentleMan
    December 15, 2009 at 9:32 am

    when I try to download "Memory Fox :: Add-ons" I keep getting : Not a valid install package – 207

  27. Anne H
    December 15, 2009 at 9:16 am

    I can't get it installed. It either gives me a Not a valid install package" or bad hash errors.

    I tried from 2 diff windows machines

  28. Alessandro
    December 15, 2009 at 8:59 am

    hi!error package is not installable

  29. sirroman
    December 15, 2009 at 8:45 am

    Fuc* Firefox, Go Opera.

    Right now I have 6 tabs (+1 which is "Downloads", so its 7 tabs). And yeah, it uses less ram that your 4 tab firefox + memoryfox.

  30. makbruno
    December 15, 2009 at 8:38 am

    Anyone willing to share this through an alternate address, as the extension is no more available on firefox add ons website. Thanks in advance.

  31. roger
    December 15, 2009 at 8:22 am

    Memory Fox has been updated today to 1.03 however when trying to download it I just keep getting :- "Not a valid install package - 207"

    • thios
      December 15, 2009 at 10:44 am

      Yup same here.

  32. Ken
    December 15, 2009 at 8:13 am

    "So what do you do? Do you stop using Firefox? Absolutely not! Will you use Internet Explorer? It is just as big of a resource hog and it causes system crashes as well (well it depends on what version you are using)."

    ...use Opera of course...

  33. Truck
    December 15, 2009 at 8:08 am

    When I used Firefox I changed a setting in my config that would trim the memory when I minimized the application. I'm not sure if it was just swapping it with the pagefile or not, but it seemed to really help me out on an old AMD Athlon XP.

  34. noone
    December 15, 2009 at 8:07 am

    Works great! Over my expectations.

    Although it wasn't enough to check the "Let me install this experimental add-on". I had to sign up and log in to finalize the installation...

  35. Anarm
    December 15, 2009 at 7:53 am

    this is great.. thanks!