Firefox 120.0.1 update fixes issue that caused 100% CPU usage on some sites

Martin Brinkmann
Dec 1, 2023

Mozilla released the first point update for Firefox 120 some hours ago. This new version addresses several performance related issues, including one that caused 100% CPU usage on sites such as Google Maps.

The new release of the browser is available already. It should be installed automatically on most devices. You may speed up the process by selecting Menu > Help > About Firefox.

Firefox opens a small overlay window. There, you see the current version of the browser. Firefox will run a check for updates and installs the latest version automatically. The page should list Firefox 120.0.1 after the required restart.

firefox 120.0.1

Firefox 120.0.1

Firefox 120.0.1 is a non-security update. It fixes a total of five different issues in Firefox.

Two of the main issues fixed in this release are performance related. The first addresses an issue that caused 100% CPU usage on certain sites, including Google Maps. Users may notice hangs on affected sites as a consequence.

According to the bug report, it was caused by incorrect loop code. You may check out the bug report here for additional information on the issue.

The second performance issue affected the start of the browser. Mozilla notes that a bug caused "persistent startup slowdowns" and that it has addressed this issue in the point release. This issue is caused by a caching issue, that Mozilla addressed in the update. More information is available on Bugzilla.

The three remaining issues are not performance related. The first addresses a startup crash on Linux, but only for some users who use aarch64 systems and only if the page sizes are not 4K.

The second fixes a green screen display issue on the video site YouTube that affects some installations. This was caused on systems with hardware acceleration enabled. Firefox would display a green video instead of the actual video. Turning off hardware acceleration restored the original functionality. Mozilla addresses the issue in the point update for Firefox.

The third and final issue fixes another video related issue. Firefox displayed the status bar in some cases when viewing fullscreen video, which it should not.

Firefox users may want to update the browser asap, especially if they are affected by one or multiple of the fixed issues in the release.

The next major release is Firefox 121, which is also the last major Firefox release of the year.

Now You: do you use Firefox? Did you run into any bugs recently?

Firefox 120.0.1 update fixes issue that caused 100% CPU usage on some sites
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Firefox 120.0.1 update fixes issue that caused 100% CPU usage on some sites
Mozilla released the first point update for Firefox 120 some hours ago that fixes several issues in the web browser.
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  1. Haakon said on December 1, 2023 at 7:13 pm

    Having embraced a never-the-dot-zero tactic over two decades ago, I would be remiss in not thanking the guinea pigs in running defense for those of us with the patience to wait on the Update for the Sake of Updating masses’ tests.

    And to be clear, the never-the-dot-zero tactic is not limited to Firefox.

  2. Herman Cost said on December 1, 2023 at 5:55 pm

    I use Firefox as my primary browser along with Windows 10 Pro, and I can’t remember ever running into any of the problems that they seem to regularly need to have updates to fix. The only problems I ever have result from my use of various privacy related adds-on, but those can easily be worked around.

    1. Windows XP 7 said on December 2, 2023 at 3:37 pm

      I use Brave as my browser, my second used to be Opera, until they came up with version 100 that changed the UI to a really ugly one and they started deleting criticism on their forums.

      I used Firefox between 2006 and maybe 2010. I liked it because it had customizability and add-ons that allowed me to install an ad blocker. When Chrome released in 2008, it was so fast that I could not believe a browser can be so fast, the only problem was that it didn’t have an ad blocker for maybe a year and until extensions became available, I kept using Firefox, but after that I switched to Chrome full time. In 2011 when Firefox 4 released and it was so slow and bloated, I gave up on Firefox completely and stuck witch Chrome until maybe 2017-2018 when I started exploring Chromium-based alternatives to stay away from Google.

      I’ve been looking at Firefox from a distance, even trying to install it a few times and use it, but it only gets worse and worse with each update. They neutered the add-ons into extensions, limited customizability and their browser code is so ancient and outdated and their rendering engine is also ancient and incompatible with many websites. Nowadays Firefox keeps spamming about privacy, as the only thing it still has to win over some paranoid people with, but for me Firefox has been a dying and outdated browser that has no chance of survival. In 3-4 years, I predict Firefox’ market share to drop to 1% and Opera to permanently surpass it and a few years later Firefox will either die or switch to Chromium itself.

  3. just an Ed said on December 1, 2023 at 1:40 pm

    No, I’ve had no problems on Linux Mint.

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