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Random lagging on Firefox.

  • 5 replies
  • 4 have this problem
  • 2 views
  • Last reply by cor-el

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Ever since the day I got the new Firefox update it has been randomly slowing down till it is "not responding". I can have other things in the background going. (Skype, WoW) and they do not lag. The CPU usage is low and normal. it is only Firefox that is slowing down. it happens on all pages at random times. if I open to Google and let it sit doing nothing at some point it will start lagging. If I wait for about 30 seconds it goes back to normal. then does it again in about 7 min, I have run several virus detectors and nothing has been found. In fact while i was writing this it happened .

Ever since the day I got the new Firefox update it has been randomly slowing down till it is "not responding". I can have other things in the background going. (Skype, WoW) and they do not lag. The CPU usage is low and normal. it is only Firefox that is slowing down. it happens on all pages at random times. if I open to Google and let it sit doing nothing at some point it will start lagging. If I wait for about 30 seconds it goes back to normal. then does it again in about 7 min, I have run several virus detectors and nothing has been found. In fact while i was writing this it happened .

All Replies (5)

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The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.

Try to decrease the value of the pref network.http.max-connections from 256 to 30 as used in Firefox 3 versions.

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That did not work. I should probably say I usually only have 1-3 tabs ever open at once.

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Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).


Another possible cause is security software (firewall) that blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.

See:

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I tried it in safe mode about 3 days ago and it didn't help at all. also I added firefox to my firewall excluded list quite a while ago. Its not stopping the page from loading. the page might be fully loaded for hours and it just randomly freezes up

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Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See: