At times, Firefox may require significant CPU resources in order to download, process, and display web content.

If you are experiencing periods of sustained high CPU usage while using Firefox, this article presents some options for you to review.

The latest Firefox version includes improvements about CPU usage. Extensions and themes can cause Firefox to use more CPU than it normally would.

In Safe Mode, extensions and themes are disabled, so if you notice a significant improvement, you can try disabling or uninstalling extensions.

Many web pages have content you don't need, such as ads, but which still use CPU resources to display its contents (see the plugin section below).

Some extensions allow you to hide bothering content: Plugins to display special types of content can consume large amounts of CPU, especially older versions.

To check to see if you have the latest versions of all your plugins, go to our Plugin Check page.

You can test to see whether one of your plugins is causing Firefox to use too much CPU by selectively disabling some of them: After disabling some of your plugins, close and restart Firefox, and observe its CPU usage.

If you don't see an improvement, you can enable those plugins again and try with a different set.

If you do see an improvement in Firefox's CPU usage after disabling a certain plugin, you may leave it disabled.

If its use is widespread on Internet, try to find an alternative lighter plugin. Check hardware acceleration is turned on and your graphic drivers are up-to-date.

For certain plugins that play videos such as Flash, the content rendering in full screen can be accelerated by hardware. Firefox stores your data in various files in your profile folder.