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Why does task manager show 6 "instances" of Firefox?

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  • Last reply by Sue

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I started using Firefox on a Windows 10 laptop. I checked Task Manager as the computer is slow. It shows 6 instances of Firefox, all 6 using memory, with one of them showing CPU usage.

Is this "normal"? Is this how Firefox works? Thanks.

I started using Firefox on a Windows 10 laptop. I checked Task Manager as the computer is slow. It shows 6 instances of Firefox, all 6 using memory, with one of them showing CPU usage. Is this "normal"? Is this how Firefox works? Thanks.

Chosen solution

Yes, this is how it works. It's not "instances", but "processes".

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Chosen Solution

Yes, this is how it works. It's not "instances", but "processes".

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It is quite normal to see more Firefox processes running.

  • one process for the main Firefox thread (user interface)
  • one or more content processes, see:
    Options/Preferences -> General -> Performance
    remove checkmark: [ ] "Use recommended performance settings"
  • a process for the compositor thread
  • a process for the WebRender when this feature is enabled
  • a process for extensions

You can find the current multi-process state on the Troubleshooting Information page (about:support).

  • "Help -> Troubleshooting Information"
    "Application Basics": Multiprocess Windows
    "Remote Processes" further down

See also the about:memory page for information about the process IDs.

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I appreciate the explanation, thanks.