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Diminishing performance (increasing lag) the longer Firefox 133 is open

John Neiberger
John Neiberger
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I believe this problem began in 133. I've noticed that if FF is open for a few hours, it starts to develop a very noticeable input lag. For example, if I'm watching a YouTube video and hit an arrow key to advance the video, there will be a couple of seconds before the browser registers the key press. It behaves like a high CPU issue but I do not detect high CPU usage when this is happening. Restarting the browser resolves the issue for a few hours.

This is happening on Windows 11 as well as on a Mac running Sonoma.

I believe this problem began in 133. I've noticed that if FF is open for a few hours, it starts to develop a very noticeable input lag. For example, if I'm watching a YouTube video and hit an arrow key to advance the video, there will be a couple of seconds before the browser registers the key press. It behaves like a high CPU issue but I do not detect high CPU usage when this is happening. Restarting the browser resolves the issue for a few hours. This is happening on Windows 11 as well as on a Mac running Sonoma.

All Replies (3)

jonzn4SUSE
jonzn4SUSE
  • Top 10 Contributor
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Have you tried Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

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John Neiberger
John Neiberger Question owner
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I haven't tried that yet. It usually takes a few hours before the problem appears and it's intermittent. It might take a while to see if it appears in Troubleshoot Mode.

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John Neiberger
John Neiberger Question owner
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Also, I'm not sure this is related, but after some time I also notice that it starts to become difficult to click on URL links. As with the other issue, restarting the browser clears it up. I believe both of these issues began in v133.

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