(Credit: Mozilla / PCMag)
I use Google Chrome and Microsoft Edge, but Firefox is still my favorite browser for Windows. It offers the tightest security and privacy among the three and handles most websites without trouble. But that doesn’t mean it always performs as it should; occasional slowdowns or freezes are inevitable. Whether you're a longtime user or a recent convert after Chrome's crackdown on ad blockers, here's how to get things working again after a glitch.
1. Adjust Hardware Acceleration
By default, Firefox tries to use the optimal performance settings based on your computer and operating system. But if you are experiencing slowdowns or related issues, you may need to adjust this manually, and one option is to tweak hardware acceleration.
With hardware acceleration turned on, Firefox uses your graphics processor to display videos, games, and animations, thereby offloading some of the burden from your CPU. With this option turned off, the browser uses the default settings. Either way, you could run into performance slowdowns and even crashes. To resolve these glitches, try turning hardware acceleration on or off depending on its current state.
To do this, open the hamburger icon at the upper right and select Settings > Tabs and browsing, then scroll down to the Performance section. If Use recommended performance settings is checked, uncheck it. You’ll see that Use hardware acceleration when available is now automatically checked.
If Use hardware acceleration when available is already checked, then check Use recommended performance settings. Firefox will turn it off and go back to the default settings. Depending on the problem you’re experiencing, you can try one setting and then the other to see which yields the most stable and reliable performance.
2. Limit the Number of Resource-Heavy Tabs
Normally, you can juggle dozens of open tabs without noticeably slowing down the browser. However, if those tabs include resource-intensive pages—think AI chatbots, video streaming services, social media sites, or video calls—you may see performance issues. If you're noticing web pages running slower than usual, see if any of these resource-heavy pages are among your open tabs. Firefox will try to prevent slowdowns by automatically unloading inactive tabs from memory, but you may also need to deal with this manually.
Open a new tab and type about:processes in the address field. The resulting page shows all the open tabs and other processes using resources. Click the Memory or CPU heading to sort the processes based on the most resource-heavy tabs. When you find the culprits, right-click on each one in the browser and select Unload Tab from the menu. That will remove the page from memory but still keep it accessible. Just click the tab when you need it, and it will reload.
3. Disable a Buggy Extension
Have you stopped to consider that a misbehaving extension could be responsible for the slowdown? Finding the responsible party can be difficult, especially if you’ve installed a lot of them. The best way to find the offending add-on is to disable them one-by-one and see if the performance issues go away. To disable an extension, click the hamburger icon, select Extensions and Themes, and flip the switch on the one you wish to disable. To completely remove an extension from Firefox, click the ellipsis icon next to its switch and select Remove.
4. Clear the Cache
Your browser’s cache stores files for the websites you visit so it doesn't have to constantly reload them from the live web. But sometimes that cache can get messed up. If Firefox is running slower than usual, clearing the cache is worth a try. To do this, go to Settings > Privacy and security, scroll down to the Browsing data section and click Clear browsing data. Click the When drop-down window and choose the duration—Last hour, Last two hours, Last four hours, or since 12:00 AM. Uncheck Cookies and site data, as you don’t necessarily want to delete all saved logins. Then check Temporary cached files and pages and click Clear.
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5. Perform a Hard Refresh on a Slow Web Page
Is a particular web page running slowly and causing issues for the entire browser? Aside from simply closing it, you can also run a hard refresh. Unlike reloading the tab or simply performing a regular refresh, running a hard refresh reloads the live page without using any cached content. Hold down the Shift key and click the toolbar icon for Reload current page. Now see if the page responds and loads normally.
6. Refresh Firefox
Running into pervasive performance problems with Firefox? Short of uninstalling and reinstalling the browser, you can refresh it to restore its default configuration. Refreshing Firefox removes all extensions and customizations, any of which could be triggering the slowdowns. Bookmarks, passwords, and website history are retained, so you don’t have to start from scratch. To perform a refresh, type about:support in the address field and click Refresh Firefox. A message explains what refreshing will do. To proceed, click Refresh Firefox. Now, restart the browser and see if the performance hiccups have gone away.
7. Troubleshoot Firefox
Still experiencing slowdowns? Firefox comes with a built-in troubleshooter that tries to narrow down problems by temporarily disabling extensions, customizations, and certain other features. To run it, type about:support in the address field and click Troubleshoot Mode. A message tells you that your extensions, themes, and custom settings will be temporarily disabled. To proceed, click Restart.
After the browser restarts, you’re placed on a page with lots of technical details. Though much of the information may be difficult to decipher, go through it to see if anything raises a red flag. Otherwise, continue to use Firefox and see if the performance issues have disappeared. If so, that points to a bad extension, theme, or setting. You can then add back extensions and themes to see if performance remains acceptable. Keep in mind that restarting the browser will re-enable everything that Troubleshoot Mode turned off.
About Our Expert
I've been working for PCMag since early 2016 writing tutorials, how-to pieces, and other articles on consumer technology. Beyond PCMag, I've written news stories and tutorials for a variety of other websites and publications, including CNET, ZDNet, TechRepublic, Macworld, PC World, Time, US News & World Report, and AARP Magazine. I spent seven years writing breaking news for CNET as one of the site’s East Coast reporters. I've also written two books for Wiley & Sons—Windows 8: Five Minutes at a Time and Teach Yourself Visually LinkedIn.
I've used Windows, Office, and other Microsoft products for years so I'm well versed in that world. I also know the Mac quite well. I'm always working with iOS, iPadOS, watchOS, and Android on my various mobile devices. And these days, I write a lot about AI, so that's become another key area for me.
My wife always jokes about all the tech products we have around the house, but I manage to put them to good use for my articles. I like Lenovo computers, so I own a couple of Lenovo desktops and several laptops. I have three MacBooks and a Mac mini. For my mobile life and work, I use an iPhone 16 Pro, iPad Pro, and iPad mini as well as an Apple Watch. But since I write about Android, I own several Android phones and tablets. Like any tech person, I have a cabinet full of cables, wires, and assorted mysterious gadgets. And when it's time to take a break from writing, I have an old Xbox 360 and Nintendo Wii, both of which I use for exercise and fitness games.
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