How to Reduce Firefox Memory Usage

Reduce Firefox Memory Usage Featured

Mozilla Firefox is a secure, reliable, and fast multi-process web browser that provides fast, stable performance with a minimal memory footprint. However, there are times when it could take up tons of memory and crash.

If you’re experiencing periods of sustained Firefox memory usage, this guide will show you some tips to reduce and/or improve it.

If you’re using a Windows PC, the easiest way to identify memory leaks in Firefox is by running the Windows Task Manager and checking for Mozilla Firefox under the Processes tab. If it’s beyond 2GB and keeps increasing with no sign of slowing down, you’re probably experiencing a memory leak.

Restart Firefox

If you leave Firefox open for a longer period of time, it tends to use more system resources. In order to resolve this, restart the browser periodically. Configure it to save your windows and tabs such that when you restart it, you’ll be taken back to your previous session.

To get the previous session’s tabs and windows back, click “Menu -> Restore Previous Session.”

Reduce Firefox Memory Usage Menu Restore Previous Session

To restart Firefox after an update, click “Restart to update Firefox” after applying any updates to the application.

Reduce Firefox Memory Usage Menu Help About Firefox Restart Update

If Firefox crashed or closed unexpectedly, either due to software errors, website issues or accidental power loss, the Restore Session page will appear when you next launch the browser. If the issue persists, though, click “Start New Session” instead.

Reduce Firefox Memory Usage Menu Restore Session Page

To configure session restore to open all tabs and windows from your previous session, click “Menu -> Options” and select General.

Reduce Firefox Memory Usage Menu Options General

Under Startup, click Restore previous session and close the about:preferences page. Your changes will now be saved automatically.

Reduce Firefox Memory Usage Menu Options General Startup Restore Sesssion

Note: Session Restore may keep you logged in to sites you signed into before closing the browser. This means that anyone using your PC after you may get access to your accounts on the sites you visited. In this case, don’t configure the browser to open your previous session’s tabs or windows.

You can also disable the default Session Restore crash recovery option to prevent previous sessions from being restored when you open the browser or it opens after an unexpected crash or closure.

To configure privacy settings for Session Restore, go to the address bar and type about:config and press Enter. In the warning page, click “Accept the Risk” and Continue.

Reduce Firefox Memory Usage Address Bar Config Accept Risk Continue

In the search box, type browser.sessionstore.resume_from_crash. Click Toggle in the grid and set to false.

Reduce Firefox Memory Usage Config Browser Session Crash

Update Firefox

Firefox updates automatically by default, but you can always do it manually. Ideally, the latest version may come with performance improvements, but you’ll only get these after restarting Firefox for the updates to be downloaded and take effect.

To do this:

1. Click the menu (hamburger icon) at the top-right corner, click Help (?) and select “About Firefox”.

Reduce Firefox Memory Usage Menu Help

2. Firefox will check for updates and automatically download them.

Reduce Firefox Memory Usage Menu Help About Firefox Updating

3. Once the download completes, restart to update Firefox.

Reduce Firefox Memory Usage Menu Help About Firefox Restart Update

Note: if the update didn’t launch, complete or something else came up, download and install the latest Firefox version from Mozilla website.

Reduce Firefox Memory Usage Systems Languages Page

You can change your update settings by clicking “Menu -> Options” and scrolling down to the Firefox Updates section.

Reduce Firefox Memory Usage Menu Options Firefox Updates

Disable themes and extensions

Resource-consuming extensions and themes can cause Firefox to use up more memory and system resources than the usual. If you want to check whether a theme or extension is causing the browser to hog resources, start it in Safe Mode and check the CPU and memory usage.

While in Safe Mode, these themes and extensions are disabled, so if you find any improvement when they’re disabled, try uninstalling or disabling them.

To start Firefox in Safe Mode, click “Menu -> Help” and click Restart with Add-ons disabled. Alternately, hold down the Shift key as you’re starting the browser.

Reduce Firefox Memory Usage Restart With Addons Disabled

Two options will appear: Start in Safe Mode or Refresh Firefox. The former will start Firefox with the default theme but disables extensions and turns off some customizations and features. This is only temporary, though. When you exit Safe Mode, all your settings will be restored to the previous state.

Reduce Firefox Memory Usage Restart With Addons Disabled Start Safe Mode

If the issue persists, it’s probably not caused by a theme or extension, but it could be because of preference settings or plugins among other causes, as these aren’t disabled in Safe Mode. If it doesn’t happen in Safe Mode though, then it’s likely that the add-ons are the culprits.

Check Adobe Flash Player and Firefox Hardware Acceleration

If you have the Adobe Flash Player plugin installed, it could be the cause of the high memory usage. Go to a page on your browser that shows a Flash video, right-click on the player and select Settings. When the player settings open, click on the icon at the lower left of the settings window to open the display panel and check whether the “Enable hardware acceleration” is checked.

Firefox hardware acceleration also eases CPU and memory usage in several cases, so you can check whether the hardware acceleration is on or off.

To do this, click “Menu -> Options -> General,” uncheck the Use recommended performance settings box, and check the “Use Hardware Acceleration when available” box.

Reduce Firefox Memory Usage General Performance Hardware Acceleration

Delete corrupt website settings file

Your profile folder holds data in various files as stored by Firefox. If the “content-prefs-sqlite” file that holds individual website settings is corrupted, delete it to decrease CPU usage.

To do this:

Click “Menu -> Help -> Troubleshooting Information” to open the corresponding tab.

Reduce Firefox Memory Usage Troubleshooting Information

Go to Application Basics and click “Open Folder” next to Profile Folder.

Reduce Firefox Memory Usage Profile Folder

Click “Menu -> Exit” and delete the “content-prefs.sqlite” file. When you open Firefox next, the profile folder will be recreated.

Reduce Firefox Memory Usage Profile Folder Content Prefs Sqlite

You can also fix memory leaks and optimize the browser’s performance by typing about:memory in the address bar, and under Free memory, selecting GC, CC and Minimize Memory usage to curtail any leaks. You can also check out other ways to troubleshoot Firefox when it crashes.

Elsie Biage
Elsie Biage

My passion has always been to share every bit of useful information I find on tech, with the ultimate goal of helping people solve a problem.

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