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Firefox uses too much Memory (RAM) - How to fix

Firefox sometimes uses more memory (RAM) than it should. This can make Firefox slower, and in extreme cases, it can even make Firefox crash. This article describes how to make Firefox use less memory. Depending on your operating system, you can review and monitor memory usage through specific tools.
Note: If you share performance data, Mozilla will gather data, including Firefox memory usage, which will help make Firefox better in future versions.

Table of Contents

  • Updating Firefox to the latest version
  • Extensions and themes
    • Disabling memory consuming extensions and themes
    • Hiding intrusive content
  • Checking Firefox hardware acceleration
  • Restarting Firefox
  • Using fewer tabs
  • Other applications using up memory
  • Memory troubleshooting tools
  • Add RAM to your computer

Updating Firefox to the latest version

The latest Firefox version includes improvements about memory usage. Update Firefox to the latest version.

Extensions and themes

Disabling memory consuming extensions and themes

Extensions and themes can cause Firefox to use more memory than it normally would.

To determine if an extension or theme is causing Firefox to use too much memory, start Firefox in Safe Mode and observe its memory usage. In Safe Mode, extensions and themes are disabled, so if you notice a significant improvement, you can try disabling or uninstalling extensions.

Hiding intrusive content

Many web pages have content you don't really need that uses memory to display. To prevent automatic loading of unwanted Flash content, use the "Ask to Activate" setting in the Add-ons Manager Plugins panel. See the Set Adobe Flash to "click to play" on Firefox article for details.

Some extensions allow you to block such unnecessary content; for example:

  • uBlock Origin allows you to hide ads on websites.
  • NoScript allows you to selectively enable and disable all scripts running on websites.

Checking Flash hardware acceleration

For certain plugins that play videos such as Flash, the content rendering in full screen can be accelerated by hardware. It eases memory usage in case of a dedicated graphics card memory.

  1. Navigate to a page that shows a Flash video.
  2. Hold down the Ctrl key while you click on the video player and click Settings… in the context menu. The Adobe Flash Player Settings screen will open.
  3. Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.
  4. Check Enable hardware acceleration is selected.
  5. Click Close to close the Adobe Flash Player Settings Window.

Checking Firefox hardware acceleration

Firefox hardware acceleration eases memory usage in case of a dedicated graphics card memory.

Restarting Firefox

Firefox's memory usage may increase if it's left open for long periods of time. A workaround for this is to periodically restart Firefox. You can configure Firefox to save your tabs and windows so that when you start it again, you can start where you left off. See Restore previous session - Configure when Firefox shows your most recent tabs and windows for details.

Using fewer tabs

Each tab requires Firefox to store a web page in memory. If you frequently have more than 100 tabs open, consider using a more lightweight mechanism to keep track of pages to read and things to do, such as:

Other applications using up memory

Having many applications running simultaneously may cause your computer to run slowly and other applications to as well. By closing down some of the unnecessary applications, memory usage will be reduced.

Memory troubleshooting tools

  • Firefox:
    • The about:memory page allows you to troubleshoot finely specific issues about memory (for instance, caused by a website, an extension, a theme) and sometimes its Minimize memory usage button may help you instantly reduce memory usage. For guidance on use of about:memory visit about:memory
    • RAMBack lets you flush many of Firefox's caches, allowing you to distinguish caching from leaking.

      Even if you're not a C++ programmer, you can try your hand at some of the tools and tips Firefox developers use to debug leaks.

Add RAM to your computer

If you exhausted all tips in the previous sections and your memory usage is still close to the maximum, maybe it's time for you to add more memory to your computer. RAM is cheap and will provide a huge performance boost.

If you have any questions, come by the Help Desk at Hardman & Jacobs Undergraduate Learning Center Room 105, call 646-1840, or email us at

KeywordsFirefox uses too much memory (RAM) - How to fix internet web browser   Doc ID82336
OwnerJohn B.GroupNMSU
Created2018-05-17 12:48 MDTUpdated2018-05-17 13:25 MDT
SitesNew Mexico State University
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