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Firefox for Mac uses excessive CPU and makes laptop run hot

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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)

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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?