Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Wo archive tread sia. Meɖekuku bia biabia yeye ne ehia kpeɖeŋu.

Firefox for Mac uses excessive CPU and makes laptop run hot

  • 1 ŋuɖoɖo
  • 67 masɔmasɔ sia le wosi
  • 9 views
  • Nuɖoɖo mlɔetɔ Waseem Yaqoob

Hawksmoor
Hawksmoor
more options

Since installing Firefox 5, or the 6 Beta, my MacBook Pro i7 15 with 8Gb RAM runs extremely hot when using Firefox. I have made comparative measurements, each after a settling period of 30 minutes:

Firefox - CPU temperature 95 degrees, fan speed 6,000 rpm, using 182% of CPU, 28 threads, and 808Mb of memory.

Chrome 12 - CPU temperature 60 degrees, fan speed 2,500 rpm, using 0.09% of CPU, 19 threads, and 70Mb of memory.

Opera 11.5 - CPU temperature 55 degrees, fan speed 2,000 rpm, using 0.04% of CPU, 6 threads, and 85Mb of memory.

It does appear that there is a major fault in Firefox to use this amount of resource - and indeed it causes the laptop to run slowly and erratically too.

Any answers to fix this? I have tried disabling plugins, no difference.

Since installing Firefox 5, or the 6 Beta, my MacBook Pro i7 15 with 8Gb RAM runs extremely hot when using Firefox. I have made comparative measurements, each after a settling period of 30 minutes: Firefox - CPU temperature 95 degrees, fan speed 6,000 rpm, using 182% of CPU, 28 threads, and 808Mb of memory. Chrome 12 - CPU temperature 60 degrees, fan speed 2,500 rpm, using 0.09% of CPU, 19 threads, and 70Mb of memory. Opera 11.5 - CPU temperature 55 degrees, fan speed 2,000 rpm, using 0.04% of CPU, 6 threads, and 85Mb of memory. It does appear that there is a major fault in Firefox to use this amount of resource - and indeed it causes the laptop to run slowly and erratically too. Any answers to fix this? I have tried disabling plugins, no difference.

All Replies (1)

Waseem Yaqoob
Waseem Yaqoob
more options

I've had this problem with Firefox 5. I deleted my profile and started a new one and the problem still persists. Also happens when I restart FF in safe mode with all extensions disabled, so I don't think they're the problem.

I'm on Lion, and didn't have such bad memory and CPU usage from Firefox before. Maybe that's something to do with it?