Memory Fox Flushes Firefox's Memory Constantly

Martin Brinkmann
Dec 12, 2009
Updated • Mar 6, 2017
Firefox, Firefox add-ons

Memory Fox is a free browser add-on for the Mozilla Firefox web browser that releases memory regularly to keep RAM usage low.

Some Firefox users feel that the web browser has grown into the wrong direction lately with too much bloat being added to the web browser.

The computer memory usage of the web browser is one of the factors that they use to make their point although studies show that memory usage actually decreased in Firefox 3 when compared to Firefox 2.

Still, the memory usage of the browser can reach hundreds of Megabytes in no time; some users notice that memory use of Firefox may grow quickly, but that it does not nearly decrease as quickly as it rises even if you reverse actions.

Memory Fox for Firefox

Memory Fox is a memory optimizer for the Firefox web browser. It is only offered for the Windows operating system and can be used to constantly flush Firefox's memory usage.

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.

Memory Fox needs to be activated after installation which can be done in the add-on's options or from the status bar icon. Activating of the memory optimizer results in constant drops in the memory usage of the web browser which can be observed in the Windows task manager.

firefox memory usage

The extension manages to keep the memory usage of Firefox 3 below the 100 Megabyte mark most of the time. This does not result in measurable speed improvements but it might be helpful if the computer system is not equipped with lots of RAM.

Memory Fox can be downloaded from the add-on's Mozilla Firefox profile page.

Update: Memory Fox's author passed away. Others have picked up development. You can download and install Memory Fox Next in Firefox for 32-bit copies of Windows for the same functionality, or Free Memory 2.0 which brings the memory optimization of about:memory to the front. You may run the tool using shortcuts, or by clicking on its icons. It furthermore supports automation on top of all that.

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Memory Fox
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  1. John said on June 11, 2022 at 7:47 am

    Does anyone know how to activate Memory Fox Next? I’m trying to use it on FF 52.9 esr but it’s not activating automatically, even after restarting FF, and there is no afom.exe in the Task Manager. Or would someone make available an copy of Memory Fox itself.

  2. Jzyehoshua said on January 20, 2014 at 1:23 am

    I decided to disable it after my internet started experiencing lag. I checked the Task Manager to see what was going and noticed afom.exe as a process I didn’t recognize, looked it up, and found this discussion. I’ve decided to disable Memory Fox after noticing afom.exe’s I/O Write Bytes are upward of 18 million and Page Faults above 60,000. This is a relatively clean computer, just purchased, so I’m not too worried about RAM right now. If I really need it cleaned up then I’ll activate Memory Fox again but in general it lags my computer too much.

  3. dawood said on June 21, 2013 at 11:43 pm

    works great for me, nothing else to say. ramback is shit.

    1. Reno Sifana Paksi said on November 7, 2021 at 1:36 am

      Hey. Why don’t you try going through Firefox’s built-in feature in about:memory to free up RAM usage. And Restart Firefox via about:profiles if Firefox slows down a bit and takes up a lot of RAM usage. and use Extensions sparingly. By the way, ever since I moved from Windows 10 to Linux around 2021 I’ve been using Firefox again. (In the past, if I’m not mistaken, I used Firefox in 2012 and moved to a Chromium-based browser because Firefox used to often display the message Script unresponsive). And don’t forget I’ve installed the Auto Tab Discard Extension to suspend inactive tabs. Homepage: (Also available for Google Chrome, Opera, Microsoft Edge Chromium, Firefox and more browsers).

  4. me said on July 1, 2012 at 9:50 am

    “…and causes increased pagefaults…”

    !!…ROFL… could it be ANY worse than bloatware-Firefox
    itself, which causes 32 freaking MILLION page-faults just sitting
    there for a few hours with NO user-input?

    I began on Phoenix many years ago, and have DISliked each new
    version more and more since FF2.0…..having gotten to the point
    now that I actually DETEST firefox…sad to say.

    A large portion of that feeling comes from the smug and callous
    developers of firefox; who spit upon the users. This is especially
    true in regards to RURAL people….in other words, the EIGHTY
    PERCENT of the human race who do NOT have broadband.
    I see this on the mozilla forums repeatedly….where someone who
    is stuck on slow dialup asks how to get FF to waste less bandwidth
    loading pics even after the Stop button is clicked; and some dev/mod
    spews vicious crap along the lines of “who cares about dialup users?”

    I ask myself this….

    WHY cannot FF load the TEXT of pages first, before any graphics?

    WHY cannot the FF-developers make the Stop button actually STOP
    the damn page loading? FF does NOT stop when one hits stop/esc,
    but continues loading the USELESS ads/graphics anyway.

    And finally, in regards to the OP about endless memory-bloating…

    WHY cannot the FF-devs RELEASE memory of each tab that is closed
    by the user? THAT is FF’s mem-hogging problem. Very ironic, since
    it is the NORM for users to -continually- open new tabs, from links on
    pages they’re scanning…and continually close tabs as they go along.
    But FF never releases the memory from those tabs….so with each
    new tab opened, the bloat just grows and grows and grows…from
    a completely NORMAL usage-pattern.

    Always the devs blame it on the add-ons…but this tab-related bloat
    goes on no matter which addons are or are not installed.


  5. Squall said on July 7, 2011 at 7:37 pm


    hey Malu, thats to be expected, RAMBACK only affects REALISTIC memory reduction,
    MemoryFox just purges all data from memory and causes increased pagefaults (disk thrashing)

  6. VW said on March 25, 2011 at 7:02 am

    Surprised I didn’t find MemoryFox on the official Mozilla Addons page so decided to comment here.

    MemoryFox is invaluable particularly in Firefox 4 for me… without the constant flushing, memory usage balloons to ~500mb and stays there with about 15 extensions and 5 tabs open. With Memory Fox enabled, mem usage hovers between 29mb (when FF4 is out of focus and idle) to 132mb (one active tab, 5 other tabs still “opened”) without appreciable performance degradation. Only caveat was that I had to remember to uncheck “Protect my system blah” when a prompt came up asking me what user to run the Memory Fox addon as in Windows XP after enabling it.

    And yes I agree with Malau – I tested RAMBack on FF4 (after having to force it to work via editing install.rdf as it wasn’t even compatible with FF4 by default) and clicked on the “Clear Cache” button that it adds to the TOols menu – it didn’t reduce memory usage at all.

  7. Malau said on March 19, 2011 at 10:51 am

    SQUALL you cut and pasted your spam at the Mozilla Forum too, the exact same message !

    ‘SQUALL’ has vested interests in the RAMBACK addon, so therefore he spews his Memory Fox lies all over the internet.

  8. Squall said on December 16, 2010 at 3:05 am

    Memory Fox’s purported Memory leak and freeing capabilities are a lie. Memory Fox uses a standard windows function to flush the process’s memory to the page file RESULTING IN WORSE PERFORMANCE.

    Any windows developer with an ounce of free thought will realise in an instant that the claims maid by the extension author are bogus and the experiences of its users are placebo. Firefox’s stability and memory use will differ from session to session, and even between reloadings of the same session, and especially differ between Windows sessions.

    The only extension which actually effects real memory usage is the ramback extension which flushes the System memory allocated caches.

    Anyone seeking to verify this, can enable the Commit column in task manager or use about:memory.

    This review will be going viral.

  9. David T. said on February 9, 2010 at 5:26 pm

    After using Firefox ever since it was Phoenix, I have switched to Chrome, now that v4 offers extension support. It is really quick and really nice. The web browser simply needs to be reinvented every few years I guess.

    1. Transcontinental said on February 9, 2010 at 5:51 pm

      I think a sort of fatality will make me slip to at least to trying Chrome… :)

  10. Transcontinental said on February 9, 2010 at 5:20 pm

    guger > I notified to the author of ‘Memory Fox’ that his extension was at this time unavailable on Mozilla Extensions’ pages. He answered me that he was preparing next version 1.4 and about to upload it. I assume last version 1.3 has been removed for a good reason that I ignore.
    So, let us wait for ‘Memory Fox’ 1.4 which should appear soon …

    1. guger said on February 10, 2010 at 6:24 am

      thank U for answer :D

      i can’t speak english very well.

      i’m so sad that because does not remain the last version :(

  11. guger said on February 9, 2010 at 5:06 pm

    oh, i want really this add-on

    but i can’t found this

    UR link page(
    print this message

    Add-on not found!

    How can i download this add-on?

    1. Transcontinental said on February 9, 2010 at 5:48 pm

      I emailed the author of ‘Memory Fox’ to let him know his extension was no longer available on Mozilla Extensions’ pages. He answered me that he was about to upload a new version 1.4. I presume the old version has been removed for a good reason, which I ignore.
      So, let us wait for version 1.4, which should be available soon.

      1. guger said on February 10, 2010 at 6:08 am

        thanks for answer :D

        I did not speak English then why did not download.

        well.. I wait for comming to nice add-on !

  12. Jojo said on January 20, 2010 at 11:26 am

    I have had a dialog with the author about these event log records.

    He says that the 2.0 release will allow for them to be disabled.

    I have removed Memoryfox until that release is available.

  13. Jojo said on January 13, 2010 at 6:24 am

    @David T. said “@Jojo: That’s more of an annoyance bug than anything. I’d rather have lots of application log entries than deal with my browser grinding to a halt.”
    Perhaps. You won’t have lots of DIFFERENT application log entries. You’ll have the same two entries from AFOM generated every two minutes, over and over and over….

    So if you ever need to examine event log records to see why an application might have a problem, well, you’ll be SOL because there won’t be anything there!

    I’ve personally never experienced FF “grinding to a halt” despite running a lot of extensions and open tabs.

    I am running on WinXP SP3 with 2GB RAM. My system has 81 processes running now. On FF (V3.5.7), I have 63 extensions and 18 plug-in’s installed. 45 tabs are open right now. FF is using about 500MB real RAM right now. I am NOT running MemoryFox.

    1. wayne k. said on January 20, 2010 at 9:43 am

      i too get these enties in the application event log for the same AFOM error as above. annoying. i am seeing them every minute or so. i have set the event log to a fixed max size with auto overwriting, but as noted, this makes it hard to see any other progs errors as the afom errors eat out the heart of the log.

      using win7 x64 & firefox 3.6rc2.

  14. David T. said on January 13, 2010 at 5:43 am

    @Jojo: That’s more of an annoyance bug than anything. I’d rather have lots of application log entries than deal with my browser grinding to a halt.

  15. Jojo said on January 13, 2010 at 4:05 am

    I’d stay away from MemoryFox for now.

    I caught a memory leak which the author fixed after my report. But I’ve also caught a problem with a process called AFOM which runs along w/MF which I ‘ve been meaning to report but haven’t got around to it yet. This app will quickly overwrite your APPLICATION section of the Windows Event log with entries like this:

    Event Type: Information
    Event Source: AFOM
    Event Category: None
    Event ID: 0
    Date: 12/27/2009
    Time: 5:08:05 PM
    User: N/A
    Computer: DESK01
    The description for Event ID ( 0 ) in Source ( AFOM ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: Requirement: [ PeriodicRAM ].

  16. David T. said on January 13, 2010 at 1:10 am

    You can have lots of RAM and still have problems with FF high memory usage… a half day’s browsing can make FF get as high as 500MB, on a 1 GB XP system FF starts hitting the pagefile and starts using several hundred MB in pagefile space… it’s insane. I will be trying memoryfox for sure.

  17. Roman ShaRP said on December 20, 2009 at 7:43 pm

    Tried it (1.08) and it seem working pretty well.

  18. sandy hayley said on December 15, 2009 at 7:10 pm

    I can’t seem to find a download site for it. What’s the deal?

  19. Jojo said on December 15, 2009 at 10:41 am

    I ran this for about 10 hours today. But had to shut it down as it has some sort of leak which results in the msg “TOO MANY WIN32 HANDLES” from my monitoring software. The program was up to 33,000+ Handles when I shut it down. That is FAR too many!

    I’ve sent a note to the developer with some screen shots.

    1. Transcontinental said on December 15, 2009 at 8:54 pm

      Looks like the developer has subscibed to your point of view ( )

      “Memory Fox Version 1.03 :
      ( 1 ). Closed Handles Left Orphaned. ( Special Thanks To Joe For Pointing This Issue Out ! )”

      Works nicely here :)

  20. Bobby Phoenix said on December 13, 2009 at 6:37 pm

    This a great tool. During the course of the day my RAM monitor would keep climbing until it reached 90%. I would normally need to close FF to force the memory dump, but with this tool, I can leave FF open all day. Yes it works, and works well. My normal routine makes the FF memory build to around 120,000k, and then it stays there, even if I close all but one tab. Now with 12 tabs open all day, it gets no higher than 25,000k, since it dumps the memory every 3 min, and starts over. GREAT tool.

  21. Transcontinental said on December 13, 2009 at 1:15 pm

    Certainly nice, but would even nicer on a system-wide basis. Try ‘CleanMem’ which handles the whole system, and it really is not to be compared to traditional memory enhancers. =>

  22. 26Dolphins said on December 13, 2009 at 1:37 am


    Using CleanMem, which does the trick for Firefox & other apps, so won’t be trying this out – at least for now.

    Funny how the very next article is about the app store Mozilla considers for add-ons (lol).


  23. nonentity said on December 13, 2009 at 12:39 am

    Oh no, my precious RAM. Seriously, the last time memory usage by a browser was a problem for me, I was using Windows 95.

  24. paul(us) said on December 12, 2009 at 8:33 pm

    Hoi Martin, Did you notice than when your activate this program this program also activates a outher program (from the same developer) named AFOM 2.0? AFOM recovers Memory Leakage within a running instance of the Firefox browser application. The disadvantage is that this gives a outher task (afom.exe) in main task management. But no worry this because the memory saving capacity from this program (Memory Fox) is absolutely fabulous. And a outher good thing is that when your close your firefox brouwser the afom.exe also disappears, in main (and of course yours) task management row.

  25. Claude LaFrenière said on December 12, 2009 at 6:27 pm

    This is totally wrong.

    Read this article from Mark Russinovich: The memory optimization haox


    1. David said on December 16, 2009 at 6:02 pm

      Claude, you’re citing an article from 2004 that discusses potential spyware/adware sold by popup ads. I think this is completely different – even though it only “manages” memory by dumping it periodically. For the way I abuse multiple tabs in Firefox, and with my old 512MB RAM laptop locking up every other day or so because it runs out of memory, that’s a very useful feature.

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