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Why would a Firefox process use 85% of my 8-core 3.5 Ghz processor even after I had exited firefox application?

  • 3 replies
  • 2 have this problem
  • 21 views
  • Last reply by cor-el

jl_morgan
jl_morgan
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I'm used to Firefox being a memory hog and never letting go of any memory it ever grabs, but this is the first time I've seen that behavior in CPU usage.

Running Windows 7 Pro, using Firefox 38.0.5 ... came up and noticed my fan was running full speed, checked applications and found Firefox using 85% of my 8-core 3.5 Ghz processor CPU with only weather.com up on screen. Exited The Firefox application and still had 85% CPU running. Checked processes and found Firefox.exe process still running and utilizing most of my CPU. Killed the process and CPU usage dropped down to only a couple of percent. Restarted Firefox, and use is probably normal now running 0 to 3 %. Anybody seen else seen this rogue process?

I'm used to Firefox being a memory hog and never letting go of any memory it ever grabs, but this is the first time I've seen that behavior in CPU usage. Running Windows 7 Pro, using Firefox 38.0.5 ... came up and noticed my fan was running full speed, checked applications and found Firefox using 85% of my 8-core 3.5 Ghz processor CPU with only weather.com up on screen. Exited The Firefox application and still had 85% CPU running. Checked processes and found Firefox.exe process still running and utilizing most of my CPU. Killed the process and CPU usage dropped down to only a couple of percent. Restarted Firefox, and use is probably normal now running 0 to 3 %. Anybody seen else seen this rogue process?

All Replies (3)

cor-el
cor-el
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  • Top 10 Contributor
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You can try to disable hardware acceleration in Firefox.

  • Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

You need to close and restart Firefox after toggling this setting.

You can check if there is an update for your graphics display driver and check for hardware acceleration related issues.

You can check for problems with current Shockwave Flash plugin versions and try this:

See also:

jl_morgan
jl_morgan Question owner
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I am not concerned with using CPU cycles while I am browsing. I can control that.

I am concerned with the thing hijacking my PC and running the thing at maximum capacity while I'm not there to monitor it after I exit the application. That single instance right there is the killer for me.

Modified by jl_morgan

cor-el
cor-el
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  • Top 10 Contributor
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Are you using "Clear history when Firefox closes" to clear any personal data/

Did you check the Windows Task Manager for leftover Firefox or plugin-container processes?

Use "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit) to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar.