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Why does sometimes firefox exhibit laggy response?

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  • Last reply by cor-el

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Sometimes on steaming sites (e.g., youtube) firefox exhibits laggy response time. For example, when I double click on the video for fullscreen, it takes about half a second for firefox to execute. This usually happens when I'm using firefox on the site without closing it for some time. Why does this happen?

Sometimes on steaming sites (e.g., youtube) firefox exhibits laggy response time. For example, when I double click on the video for fullscreen, it takes about half a second for firefox to execute. This usually happens when I'm using firefox on the site without closing it for some time. Why does this happen?

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Enter about:config in the url bar, find full-screen-api and try to set the following preferences to 0:

  • full-screen-api.transition.timeout
  • full-screen-api.warning.delay
  • full-screen-api.warning.timeout
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The problem doesn't occur all the time. It mostly occurs after I've roamed around a particular website in a single tab for a certain amount of time (e.g., after auto streaming youtube for an hour). And also, the lag is not only associated with going in and out of fullscreen mode. The lag is universal to that particular tab. No matter what I do in the tab, it feels slow to respond. It takes more time for firefox to respond to a click on that tab. The lag goes away if I simply change the tab, or restart firefox.

Modified by Hiroshi Ahsan

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Maybe there are memory issues.

You can check the Firefox Task Manager (about:performance) and about:memory pages.