Yup, same here.

Ubuntu Lucid 10.04

Even sitting idle with firefox open is using 90% of my cpu.

Ridiculous

Going to stop using firefox if issue is not fixed!!

You can create a new profile as a test to check if your current profile is causing the problems. See [[Basic Troubleshooting|#Make_a_new_profile|Basic Troubleshooting:Make a new profile]]

There may be extensions installed by default in a new profile, so check that in "Tools > Add-ons > Extensions".

If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files). See http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

This is a major problem for mac users. This kind of error would totally prevent anyone using a mac from using Firefox.

For me at least, it's using an entire Gigabyte of memory on 'Firefox-bin'.

Usual reason for this issue is bad written extension or plugin. Can you post the result of about:support page?

Same here CLI: top confirms 99-100% CPU usage. So far it hasn't diminished my browsing experience, but my laptop is getting hot which made me look at what was just plain running away with the goodies Gateway gave me.

 Application Basics

       Name
       Firefox

       Version
       4.0

       User Agent
       Mozilla/5.0 (X11; Linux x86_64; rv:2.0) Gecko/20100101 Firefox/4.0

       Profile Directory

         Open Containing Folder

       Enabled Plugins

         about:plugins

       Build Configuration

         about:buildconfig

 Extensions

       Name

       Version

       Enabled

       ID

       Global Menu Bar integration
       1.0.2
       true
       globalmenu@ubuntu.com

       Ubuntu Firefox Modifications
       0.9
       true
       ubufox@ubuntu.com

       Hide Menubar
       4.0.20110415
       true
       hidemenubar@moztw.org

       Firebug
       1.7.0
       true
       firebug@software.joehewitt.com

       LastPass
       1.72.0
       true
       support@lastpass.com

       Rainbow
       1.0
       true
       rainbow@colors.org

       DownThemAll!
       2.0.2
       true
       {DDC359D1-844A-42a7-9AA1-88A850A938A8}

 Modified Preferences

     Name

     Value

       accessibility.typeaheadfind.flashBar
       0

       browser.places.smartBookmarksVersion
       2

       browser.startup.homepage
       http://www.google.com/

       browser.startup.homepage_override.buildID
       20110419192255

       browser.startup.homepage_override.mstone
       rv:2.0

       extensions.lastAppVersion
       4.0

       network.cookie.prefsMigrated
       true

       places.database.lastMaintenance
       1304145111

       places.history.expiration.transient_current_max_pages
       124603

       privacy.sanitize.migrateFx3Prefs
       true

 Graphics

       GPU Accelerated Windows
       0/1

This worked for me :)

• 1. Open Firefox
• 2. In the address bar type in about:config
• 3. A warning will appear, click the button that says “I will be careful” (if you already have not told it to warn you)
• 4. Near the top of a VERY long list you will see an empty box next to the word Filter:
• 5. Type in dom.ipc.plugins.enabled that will shrink the list down to 5 items
• 6. The first one on the list is the one you are concerned with, right click on that entry and click on Toggle, that will change the value on the right from True to False
• 7. Restart Firefox

Thanks RealRonin. It worked for me in ubuntu 10.04 LTS w/ FF 6.01

No Problem glad it helped :), and this fix also works for Windows machines that have firefox.exe (Windows version of firefox-bin) still running. I have done this on my Ubuntu 10.04, Windows XP, Vista and 7 all with the same success, sadly I do not have a MAC to test it on.

It works sometimes, but not every time, though in dome.ipc.plugins.enabled always False is on. Sorry, this is no permanent solution.