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High CPU usage on OS X 10.9.4

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So I have high CPU usage of 50-70% and in safe mode goes away, however when I disable all extensions and set add-ons to "ask to activate" it shoots high when not in safe mode, I disabled themes and everything. I am at my wits end as my Macbook Pro has a Core i5 and 16GB of DDR3 RAM, with a 750GB SSD Hard drive, the hardware is perfectly fine, and firefox is the issue. I may have multiple tabs open a lot but even with 1 or 2 tabs it shoots to an average of 40-50% and as high as 140%

So I have high CPU usage of 50-70% and in safe mode goes away, however when I disable all extensions and set add-ons to "ask to activate" it shoots high when not in safe mode, I disabled themes and everything. I am at my wits end as my Macbook Pro has a Core i5 and 16GB of DDR3 RAM, with a 750GB SSD Hard drive, the hardware is perfectly fine, and firefox is the issue. I may have multiple tabs open a lot but even with 1 or 2 tabs it shoots to an average of 40-50% and as high as 140%

All Replies (5)

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You can try to disable hardware acceleration in Firefox.

  • Firefox > Preferences > Advanced > General > Browsing: "Use hardware acceleration when available"

You need close and restart Firefox after toggling this setting.

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Already tried that, still no difference

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If it works in Safe Mode and in normal mode with all extensions (Firefox/Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit)

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After a while it spools to 100% CPU. I disabled what I thought were the trouble causers such as RSS ticker. But now I am here again with 104% CPU