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Insanely high memory and I/O usage after upgrading from 11 to 12


I just installed Firefox 12 and memory usage on 40 open tabs spiked from a maximum of 900 MB-1 GB to 2.5 GB. Memory usage for firefox.exe would start at 4-500 MB, steadily increase to 2.5 GB in 10-20 min even if I did not touch the browser at all. Hard drive I/O went trough the roof as well. Laptop would become unresponsive and Firefox would eventually crash. Downloaded Firefox 11, installed it on top of Firefox 12 and everything is back to normal, memory usage is less than 900 MB with normal usage, it doesn't really grow past that. Guess will stick with 11 until they fix these issues in 12.

Modified by NWAVES

Additional System Details

This happened

Every time Firefox opened

This started when...

after upgrading from Firefox 11 to Firefox 12

Installed Plug-ins

  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • Shockwave Flash 11.2 r202
  • Adobe PDF Plug-In For Firefox and Netscape 10.1.3
  • Version
  • Google Talk Plugin Video Accelerator version:
  • Google Update
  • iTunes Detector Plug-in
  • Next Generation Java Plug-in 1.6.0_31 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Adobe Shockwave for Director Netscape plug-in, version
  • 5.0.61118.0
  • AmazonMP3DownloaderPlugin 1.0.15
  • GEPlugin
  • The plug-in allows you to open and edit files using Microsoft Office applications
  • Office Authorization plug-in for NPAPI browsers


  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20100101 Firefox/11.0

More Information

Thinkpad T60p, Win 7 64 bit, Core 2 Duo T7200, 4GB RAM. Extendions: ABP 2.0.3, DownThemAll 2.0.13, GreaseMonkey 0.918, Kaspersky AntiBanner, URL Advisor and Virtual Keyboard v. Disabling GreaseMonkey did not make a difference, Did not try to disable the other add-ons or extensions.

Mike 0 solutions 32 answers

You've got 100 processes running. It looks like you've got a lot of third party stuff running in the background.

I have only 36 with FF running - 2 for FF and 2 for AdAware- the remaining 32 are mostly Windows.

vipanonymous 0 solutions 3 answers

Only one tab. I tried the FF 13 beta and it's working fine to me, i hope when the final version comes out there's no big changes..

Mike 0 solutions 32 answers

I have two windows open right now and have been hopping all over the place on the Internet all morning. I'm at 225K with FF and 62K with plugins. Note your Firefox and Plugin container sizes. I took this capture with no keyboard activity.

Modified by Mike

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I'll stick with what works for now until people quit having massive problems with 12 then consider upgrading. If it ain't broke, I ain't fixing it.

MikeWilson Thanks for your posts, but please remember firefox 9 is not secure if you are happy to take the risks so be it.

If you would lie to try to get your system working with the current Firefox Release (currently fx 12), or find out which add-on; or whatever; caused the problems when you use firefox 12 then please start a new thread. (And post here when you do so. I am sure all many readers will be interested in the results).

I strongly suspect problems will turn out to be with other software interactions and will not get fixed by Firefox changes.

It is probably incorrect to sate

I'm NOT having any security, crash, memory leaks or any other problems

because Firefox 9 is intrinsically NOT secure. The fact you are using security software is not likely to remove all risks.

You have already suggested that the latest version of AdBlock may be one of the problems.

You say

Next was upgrading to 2 Gig of ram and turning off the PAGE FILE. This lets FF run out of RAM instead of the hard drive and eliminates a lot of fragmentation on the HD from heavy surfing. This also solved memory leak problems. 

Increasing to 2GB of ram is probably a good move for a variety of reasons.

Note on some Windows systems, I believe, setting page file to a fixed maximum size, rather than a variable range may reduce fragmentation of the page file itself. Firefox, and systems in general will slow down when using a page file rather than RAM, but that does not necessarily mean having no page file is always good. This is however leaning towards being a discussion relating to OS tweaks and not appropriate to this forum.

Transferring cache to a flash drive, or for that matter even another HDD spindle could speed things up, but again not really on topic for this forum. Disabling unused plugins, and stopping unused background applications is again good general advice, that you have given.

Mike 0 solutions 32 answers

Fragmenting the HD where FF may be operating out in virtual memory of is a problem, one which I solved by removing the CACHE to flash drive and the other by taking control of Windows lousy memory management. I have photos on main site. Spybot has its own internal browser security for both IE and FF.

To each his own. This old Dell Optiplex 270 with 2 Gig of RAM runs like a bat out of hell even with FF. I still sticking with what already works instead of trying to debug FF12. I am also sticking with my statement about not having any of the aforementioned problems since I'm no having them. My Task Manager somewhat speaks for itself.

Modified by Mike

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Great to hear that you are having no problems after changing from Firefox 12 release to Firefox 13 beta.

That presumably will also have resulted in use of a new profile and possible extension changes, factors that may themselves contribute to a solution. Note Firefox 13 is due out early next month as the Release.

As a general note my personal opinion is that it using the Beta channel almost routinely could be a good idea. A big advantage is that once you are on it and have had it for a couple of months you will always have the knowledge that
if you run into a problem you have a downgrade option because it is relatively easy to install the Release version and you will have already tried that while it was in beta and can be fairly certain it will work flawlessly,

Mike 0 solutions 32 answers

Once Firefox comes out with something that people aren't complaining about everywhere, I'll check into it - online reviews.

Rushing into something like all the people buying phones when they first hit the market then taking them back by the truck loads, happens all the time. If 13 turns out to be pain, I can always reinstall 9.

A large majority of problems here seem to be with FF12. It's looking like Windows Vista - too buggy.

Modified by Mike

Mike 0 solutions 32 answers

This entire forum is full of problems with people who recently upgraded to version 12. Google also shows pages full of others having the same problem. Most of the info here and there shows problems being resolved with 13 Beta.

I wouldn't waste my time experimenting with 12 if it's that big of a widespread problem. Try 13 and see if its as a good as 11 or better. If you still have problems with 13 and had no problems with 11, then go back to 11 until Firefox gets the kinks out of everything.

It should be noted that with my current setup, I can watch memory decrease back to original amount as I close out windows and leave Yahoo email open.

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I do agree it is worth trying the beta channel

The problem may be being resolved by the new profile used in Firefox beta, if that is the case the standard Firefox 13 may not resolve the problem whereas for instance creating and using new Firefox 12 profile may solve the problem now.

Lets remember this only affects a very, small proportion of the nearly 1/2 a billion users. It may still affect a lot of users but probably as a common symptom of several varied problems. Doing nothing will not result in a magic fix.

wandajoy 0 solutions 1 answers

Disabling JAVA next generation reduced my usage from 400M+ to 130M Control panel > Java > Advanced > Java plug-in > next gen

Thanks to the posters who suggested this ! https://support.mozilla.org/en-US/questions/927004

Win2k FF 12 Java AB+ FB NS Foxit VLC

Modified by wandajoy

dharding 1 solutions 3 answers

I have been having these issues as well. Firefox memory usage will balloon insanely high (2-3GB after a few minutes of light browsing). Sometimes it will drop back down to a more reasonable level (a few hundred MB), sometimes it hangs (presumably while trying to garbage collect everything), and sometimes it crashes in the garbage collection code (https://crash-stats.mozilla.com/report/list?signature=js%3A%3Agc%3A%3AMarkChildren%28JSTracer*%2C+js%3A%3Atypes%3A%3ATypeObject*%29).

I was able to capture an about:memory report when Firefox had gotten to about 1.5 GB and have attached an image.

Don't know if any of this helps or not. I'm looking forward to trying Firefox 13 when it comes out.

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hello dharding, we can probably offer you better help, when you open your own question and provide more detailed information about your system (copy it from help > troubleshooting information).

tackling memory leaks in the browser is a top priority of mozilla & much progress has been made over the last months. such high memory consumption as you've described is most commonly caused by leaking addons & plugins nowadays...

dharding 1 solutions 3 answers

Created a new question: https://support.mozilla.org/en-US/questions/928367.

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2045 solutions 8899 answers

thank you, will post my suggestions there!