Why Does Firefox Use so Much Memory & How to Reduce High Usage

Some browsers are more efficient than Firefox

by Loredana Harsana
Loredana Harsana
Loredana Harsana
Managing Editor
Loredana is a passionate writer with a keen interest in PC software and technology. She started off writing about mobile phones back when Samsung Galaxy S II was... read more
Fact checked by Alex Serban
Alex Serban
Alex Serban
Windows Server & Networking Expert
After moving away from the corporate work-style, Alex has found rewards in a lifestyle of constant analysis, team coordination and pestering his colleagues. Holding an MCSA Windows Server... read more
Affiliate Disclosure
  • If Firefox is using too much memory, it might be clogged by extensions or unnecessary settings.
  • So to cut on Firefox RAM usage, you will need to check and tweak several browser settings.
  • In the end, if all these don't solve the Firefox high memory usage problem, try a lighter browser.
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Firefox is one of the best web browsers for all devices. However, it is not without its issues, one of them being the report from users that it uses too much memory on their Windows PC.

This affects the performance of Firefox and the other programs and processes running on the computer. This makes it all the more important to identify and eliminate the underlying cause.

So, here is all you need to know about why Firefox is using too much memory and the best solutions for it.

Why does Firefox use so much memory?

There are a few factors that can make Firefox use so much memory. Below are some of the prevalent ones:

  • Faulty extensions and themes: If Firefox uses excessive memory, you must first check your extensions and themes. While these can improve your PC’s functionality and aesthetic, they can considerably increase memory usage. The solution is to disable or remove these extensions and themes.
  • Outdated browser: In some cases, Firefox might take up lots of memory because your browser is outdated. In this case, the solution is to update your browser.
  • Disabled hardware acceleration: The hardware acceleration feature helps to maximize resource usage, especially when you are playing media. If this feature is disabled, your memory and CPU usage can increase exponentially.

How can I fix Firefox if it’s using a lot of memory?

Before making changes to your browser to fix this issue, try the following troubleshooting steps:

  • Restart Firefox.
  • Close unnecessary tabs.
  • Close other apps.

1. Switch to a different browser

The quickest and most hassle-free way to get back online without errors is to use a different browser.

If Firefox keeps using tons of resources, we suggest you try a lightweight alternative like Opera GX. This browser aims to load pages fast, even on lower-end PCs.

That is why it implements dedicated features like RAM and CPU limiters. YOu can easily enable them, and the browser will not bypass the limits, hence offering peak performance.

Using other apps while browsing the web can become demanding, but if you enable the bandwidth limiter feature and set how much data you want to allocate to your browser, your other apps will run faster too.

Opera GX

Open as many tabs as you want and load pages fast with this performance-oriented browser.

2. Update Firefox to the latest version

  1. Click the hamburger icon on the top right corner and select Help from the menu.
    help firefox using a lot of memory
  2. Next, click on About Firefox.
    about  firefox using a lot of memory
  3. A new window will now appear. Check if Firefox is up to date.
  4. If your version is outdated, Firefox will download the latest version automatically.

After updating Firefox to the latest version, check if the Firefox is still using too much memory

3. Start Firefox in Troubleshoot Mode

  1. Click the hamburger icon to open the Firefox menu, and select Help.
    help firefox using a lot of memory
  2. Now, click on Troubleshoot Mode here.
    troubleshoot firefox using a lot of memory
  3. Finally, click on Restart in the confirmation prompt that pops up.

Expert tip:


Some PC issues are hard to tackle, especially when it comes to missing or corrupted system files and repositories of your Windows.
Be sure to use a dedicated tool, such as Fortect, which will scan and replace your broken files with their fresh versions from its repository.

Firefox will now launch with extensions and other custom settings disabled, and if it works fine, you know what’s using too much memory.

So, disable extensions one by one, or revert any changes made to the browser setting and see how it behaves. Hopefully, you’ll find the problematic plugin in no time.

4. Disable themes and extensions

  1. Launch Firefox, and press Ctrl + Shift + A to open the Add-ons and themes.
  2. Now, click the Extension option in the left pane.
  3. Toggle off the switch for each extension to disable it and restart your PC.
  4. If this resolves the issue, repeat Steps 1 and 2, and click the three vertical dots before the fault extension.
  5. Choose the Remove option.
    remove firefox using a lot of memory
  6. Now, select Themes from the tabs on the left.
  7. Click the Enable button for the System theme-auto.

After selecting the Default theme, restart Firefox, and check if it still uses a lot of memory. Many users like to customize Firefox with new themes and improve the browser’s functionality with extensions.

Although the experience can be impressive, it can later cause your browser to hog your system resources.

5. Use about:memory feature

  1. Launch Firefox, paste the following path in the address bar, and hit Enter:about:memoryabout memory firefox using a lot of memory
  2. On this page, you can view detailed reports regarding memory usage.
  3. You can also easily free your memory by clicking the Minimize memory usage button in the Free memory section.

One of the excellent built-in features of Firefox is the memory and performance optimizer. Using the memory tool, you can reduce or stop Firefox from using a lot of memory.

6. Enable hardware acceleration

  1. Launch Firefox, click the Menu button (three horizontal lines), and select the Settings option.
    settings firefox using a lot of memory
  2. Scroll down and uncheck the box for Use recommended performance setting under the Performance section.
  3. Now, check the box for Use hardware acceleration when available and restart your browser.
    performance firefox using a lot of memory

Hardware acceleration is one of the superb features on modern browsers that help with load sharing. It is especially useful when playing a media file as it transfers some load from your CPU to the GPU.

If this feature is disabled, it can strain your PC resources, including the memory. So, you need to enable it to get the best performance from your browser.

7. Reset your browser

  1. Click the Menu button on Firefox and select the Help option.
    help firefox using a lot of memory
  2. Choose More troubleshooting information.
    more troubleshoot
  3. Now, click the Refresh Firefox… button.
    refresh button
  4. Click the Refresh Firefox button again to confirm the action.
    refresh firefox using a lot of memory
  5. Finally, Firefox will restart and bring the list of your imported info. Click the Finish button to reset them all.

If the fixes above do not stop Firefox from using many resources, you need to reset Firefox to default. This will clear up the settings you might have made to the browser that might be causing the problem.

Firefox using too much memory is a major concern, and you should now be able to fix it by using one of our solutions listed above.

If you are experiencing memory leaks on Firefox, check our detailed guide to fix it.

Feel free to let us know the solution that worked for you in the comments below.

Still experiencing issues?


If the above suggestions have not solved your problem, your computer may experience more severe Windows troubles. We suggest choosing an all-in-one solution like Fortect to fix problems efficiently. After installation, just click the View&Fix button and then press Start Repair.

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