Firefox uses too many CPU resources - How to fix
- Revision id: 775
- Creator: Chris_Ilias
- Comment: add missing word from previous edit
- Reviewed: No
- Ready for localization: Yes
- Readied for localization by: AnonymousUser
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 CPU (Central Processing Unit) is the "brain" of the computer. When the CPU is being heavily used, the overall performance of the computer can be impacted.
- Depending on your operating system, you can review and monitor CPU usage through specific tools. On Windows, the Performance tab of the Windows Task Manager displays the rate of CPU consumption.
Table of Contents
Using AVG Security Toolbar
A recent update by AVG to its AVG Security Toolbar extension caused Firefox to use significantly increased amounts of CPU and memory. This is a bug in the extension that AVG is working on fixing. For the time being, you can disable the extension.
- At the top of the Firefox window, click on the menu and select . The Add-ons window will appear.
- Select the panel.
- In the Extensions panel, select AVG Security Toolbar.
- Click the button.
- Click . Firefox will close, then open with the extension disabled.
Only on specific pages
If high CPU usage occurs only while visiting specific websites, the following areas should be reviewed to identify the common issue.
Some websites, such as YouTube, require a plugin called Flash. The Flash plugin is used to display animated or video content inside the web browser window. This plugin is updated regularly, and some sites require the latest version of the plugin to be used.
- Download and install the latest version of the Flash plugin For more information, see Flash.
- A Firefox add-on, called Flashblock, allows you to selectively enable and disable Flash content on websites.
The Adobe Reader plugin enables the display of PDF documents inside the Firefox browser. The plugin is the browser component of Adobe Acrobat Reader, a free tool for reviewing and printing PDF documents. If the problem seems to be occurring when you access PDF documents:
- Try updating Adobe Reader. For more information, see Adobe Reader.
- You can configure Firefox to open PDF documents outside of Firefox. For more information, see viewing PDF files outside of Firefox.
Report the website
If you are unable to determine the source of the problem with a specific site, you can report the site to the Firefox development team, which can review the site to determine if there are specific issues in Firefox that need to be addressed.
- To report a website, at the top of the Firefox window, click the menu, and select .
- Note: No personal information is required to submit a report of a broken website. Reporting issues with specific websites assists the Firefox team in improving the browser.
On every website
Extensions for Firefox are developed by a community of thousands of individuals spread around the world. These individuals are responsible for the content of their extensions. Sometimes, CPU usage problems can occur due to varying development standards, incompatibility between extensions, and insufficient support for newer versions of Firefox. For more information, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.
Disabling cursor and bitmap hardware acceleration on some video cards and drivers can reduce CPU usage when displaying images. For more information, see the documentation that came with your video card.
Windows Compatibility mode
Windows Compatibility mode enables the execution of Windows program in an environment that mirrors earlier versions of the operating system. For example, you can execute Firefox in a Windows XP environment that is running the program as if the operating system was Windows 95.
Running Firefox on Windows in Compatibility mode has been known to cause high CPU usage. To stop Windows from running Firefox in Compatibility mode:
- Find the firefox.exe file. Typically, this file is located here:
C:\Program Files\Mozilla Firefox
- Right-click the Firefox icon, and select to open the Mozilla Firefox Properties window.
- Select the Compatibility tab, and make sure Run this program in compatibility mode for: is deselected.
Newer versions of Windows utilize a mechanism to accelerate the boot process. On Windows XP and Vista systems, the operating system must load many individual pieces of files during the boot-up process for the operating system and applications. Windows maintains a record of the pieces that are loaded during the boot process in a folder. Subsequent rebooting can use this trace to identify files that would be more efficient to load entirely at one time, instead of loading individual pieces across multiple reads of the hard disk. This prefetch mechanism can accelerate the overall performance of the computer.
However, the method of deciding which files to load may not be efficient for Firefox and can require significant CPU resources. You may experience faster performance by removing prefetch files on Windows XP or Windows Vista systems. The prefetch files are stored here:
Delete any filename beginning with: FIREFOX
Based on information from Firefox CPU usage (mozillaZine KB)