3 ways to prevent Firefox from consuming CPU resources

3 ways to prevent Firefox from consuming CPU resources
3 ways to prevent Firefox from consuming CPU resources

Firefox has a reputation for consuming a lot of processor resources and being difficult to scale down to a lighter browser. However, if your processor is running at 100% during basic web browsing, there is a problem. Check your extensions and modules and change your system settings if necessary.


Method 1 of 3: Troubleshoot extensions

Stop Firefox from Consuming CPU Cycles Step 1

Step 1. Start Firefox in Safe Mode

Type about: support in your address bar to display the Troubleshooting Information page. First click on Restart with modules disabled. When the command prompt appears, select Safe Mode. All modules will be disabled during this session. Navigate as you normally would and check the CPU usage. If Firefox consumes significantly less resources in Safe Mode, continue to the next step. Otherwise, try another method.

  • You can also open this page by clicking on the menu icon, then the question mark icon and finally Troubleshooting information.
Stop Firefox from Consuming CPU Cycles Step 2

Step 2. Disable an extension

Quit and restart Firefox to return to normal mode. Type about: addons in the address bar to display the add-ons manager. Click on the tab Extensions then click Deactivate to temporarily deactivate an extension. If you are asked to restart Firefox, do so. Browse for some time with the extension disabled and check the CPU usage.

  • This page lists extensions with known issues and their solutions. It is not complete and up to date, but it is a good place to start.
  • The main culprits are antiviruses, ad blockers, and Adobe Reader extensions. Start there.
Stop Firefox from Consuming CPU Cycles Step 3

Step 3. Repeat with other extensions

If the CPU usage has not decreased, turn off another extension and navigate to Firefox. Continue until the CPU usage has decreased. The last deactivated extension is probably to blame. Turn it off until you need to use it.

Many extensions can consume processor resources even if all are functioning perfectly. If so, turn off anything you don't use often

Stop Firefox from Consuming CPU Cycles Step 4

Step 4. Go back to your default theme

If your problem persists, chances are your problem is with a custom theme. Click on the tab Appearance in the add-ons manager and enable the default theme.

Method 2 of 3: Troubleshoot modules or plugins

Stop Firefox from Consuming CPU Cycles Step 5

Step 1. Update your modules

Go to https://www.mozilla.org/en-US/plugincheck/ to check the status of all your modules. If you see the Update Now button, click on it and wait for the update. Restart Firefox after updating. Modules increase the consumption of processor resources when watching videos, PDFs or other media.

Stop Firefox from Consuming CPU Cycles Step 6

Step 2. Modify the behavior of the modules

Once all the modules are up to date, it will be very easy to test them.

  • Click on the tab Plugins in the Add-ons Manager.
  • Click on each drop-down menu that says Always activate and select Ask to activate.
  • Navigate as usual. A window will appear each time a module requests its activation. If you select Yes and as the CPU usage increases, you've found the problem.
  • Once the problem is identified, find and install similar modules to replace it. If you can't find one, leave it in mode Ask to activate.
Stop Firefox from Consuming CPU Cycles Step 7

Step 3. Install new extensions

Install new extensions to resolve content issues. One solution is to block the media that you don't want to show. Try the extensions below.

  • If the problem is caused by Flash, install Flashblock.
  • If it is caused by JavaScript, install NoScript. Disabling problematic scripts one by one will be a bit laborious at first.
  • To decrease overall CPU usage, install Adblock Plus or another ad blocker.
Stop Firefox from Consuming CPU Cycles Step 8

Step 4. Reset Firefox

If all failed, reset Firefox. This will permanently remove your extensions, but preferences and bookmarks should remain intact. To reset Firefox, go back to about: support and then click Repair Firefox.

Try the solutions below before making that decision, but if Safe Mode fixes your problem, there's a good chance that extensions are the cause

Method 3 of 3: try other solutions

Stop Firefox from Consuming CPU Cycles Step 9

Step 1. Update Firefox

Check your version of Firefox to automatically download the most recent version. If you've updated it already, download the beta instead. The beta version includes fixes for ongoing issues that have not yet been installed on the classic version of Firefox.

It is not recommended to downgrade to older versions of Firefox for security reasons

Stop Firefox from Consuming CPU Cycles Step 10

Step 2. Remove malware from your computer

If you see pop-ups and advertisements on all of your web pages, there is a good chance that your computer is infected with malware. Even if it's not sure, run a virus scan. Malware consumes processor resources.

Stop Firefox from Consuming CPU Cycles Step 11

Step 3. Disable Windows Compatibility Mode

If you are using Windows, right click on the Firefox icon on your desktop. Select Properties then click on the tab Compatibility. If the box under Compatibility Mode is checked, uncheck it and restart Firefox.

Stop Firefox from Consuming CPU Cycles Step 12

Step 4. Enable hardware acceleration

Hardware acceleration assigns some of the hard work to the GPU, which in theory takes the strain off the processor. Usually it works as expected on Firefox, but it may not work properly on some websites or on computers using an old operating system or graphics card. Activate hardware acceleration every other day to compare its effects.

  • Type about: preferences # advanced in the Firefox address bar or click on the icon menu (all 3 lines), Preferences then Advanced.
  • Check or uncheck the box Use hardware graphics acceleration if available.
  • Restart Firefox.
Stop Firefox from Consuming CPU Cycles Step 13

Step 5. Enable hardware acceleration for Flash videos

Your Flash player can use hardware acceleration even if Firefox has it turned off. Right click on a Flash video and select Settings. Click on the leftmost tab and check or uncheck Enable hardware acceleration. Adjust this setting according to your Firefox settings.

Some video hosts use an HTML5 player, not Flash. It should adjust correctly to your Firefox settings

Stop Firefox from Consuming CPU Cycles Step 14

Step 6. Disable WebGL

WebGL can best be described as a hardware acceleration technology, most of the time used for heavy graphics use, such as 3D browser games. It was once known to consume processor resources, but these problems are rare on the latest versions of Firefox. You can try to turn it off, just in case.

  • Type about: config in the address bar. Like the warning says, don't change a thing if you don't know what you're doing.
  • Look for webgl.disabled. Do not confuse this with other similar settings.
  • Double click on the column to change the value to True.
  • Restart Firefox.


  • Hardware acceleration generally decreases the frequency of the processor, but it does not necessarily reduce power consumption.
  • Hardware acceleration will be more efficient if you update your graphics card drivers.

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