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Firefox 18 slowing down over time

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New User

Firefox 18 slowing down over time

I'm running Firefox 18.0.1 under Windows 7, all updates current, on a Dell M6700 I7, 2.77Ghz, 8Gig ram. When I first start Firefox, it runs fine. After about 30min, it gets slow. the bookmark memu takes several seconds to draw, sites take several seconds to load/reload. This was not a problem with the same version under Windows XP using even more plugins and extensions.

If I quit and restart Firefox, it runs fast for awhile, then slows down again.

I've tried turning off most extensions and plugins and the problem does not change.

14 REPLIES
Site Moderator

Re: Firefox 18 slowing down over time

Which security software (firewall, anti-virus) do you have?

A possible cause is security software (firewall,anti-virus) 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 and the plugin-container 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:


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

See "Creating a profile":

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

New User

Re: Firefox 18 slowing down over time

I tired shutting off all security software and disabled the firewall with no effect. I didn't really expect any change since quiting and restarting Firefox temporarily solves the problem. This has the feel of a memory leak.

Site Moderator

Re: Firefox 18 slowing down over time

Did you try a new clean profile?

New User

Re: Firefox 18 slowing down over time

Yes, I created a new user acct to make sure it was clean. Watching memory with the Resource Monitor is showing memory for all four categories going up over time. At launch they are 242812, 228056, 52120, 175928 After about 30min of browsing: 580996, 598384, 84984, 513400

Site Moderator

Re: Firefox 18 slowing down over time

You can check the about:memory page and try to click the button at the bottom to minimize the memory usage to see if that helps.

New User

Re: Firefox 18 slowing down over time

Same problem here. Tried the new profile, no addons, mimimize memory but the problem continues.

Site Moderator

Re: Firefox 18 slowing down over time

Does it help if you run Firefox in Safe mode?

In Firefox Safe mode these changes are effective:

  • all extensions are disabled
  • the default theme is used (no persona)
  • userChrome.css and userContent.css are ignored
  • the default toolbar layout is used
  • the Javascript JIT compiler is disabled
  • hardware acceleration is disabled

Try to disable hardware acceleration in Firefox.

New User

Re: Firefox 18 slowing down over time

A lot better with the hardware accelaration disabled! For the record my laptop uses Nvidia Optimus with a Nvidia NVS 4200m (Driver 9.18.13.697) for graphic intensive apps and an Intel HD (8.15.10.2418) for 2D apps.

Regular User

Re: Firefox 18 slowing down over time

Have you tried the following yet

How to make firefox faster