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Firefox is still using too much CPU/RAM after Quantum update

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I have returned to Firefox this week after the new release of Quantum, and I really want it to work. However, I am still experiencing the same problems that caused me to stop using Firefox previously: it consumes too much CPU resources and RAM. Although it is a little faster than before, it is still noticeably slower compared to other browsers ie Chrome. Also, the computer heats up and the fan starts running when I view webpages via Firefox. Facebook is the worst, but it happens on other pages as well.

I have a 2011 MacBook Pro. Perhaps my computer is part of the problem, but none of these issues arise with other browsers.

I am not interested in the lengthy fixes that are suggested in the existing articles on issues of using too much CPU/RAM. I thought that this new release was going to address these problems.

Does anyone have any ideas? I have attached a screenshot of my activity monitor while using Firefox to browse Facebook.

Thank you for your help.

I have returned to Firefox this week after the new release of Quantum, and I really want it to work. However, I am still experiencing the same problems that caused me to stop using Firefox previously: it consumes too much CPU resources and RAM. Although it is a little faster than before, it is still noticeably slower compared to other browsers ie Chrome. Also, the computer heats up and the fan starts running when I view webpages via Firefox. Facebook is the worst, but it happens on other pages as well. I have a 2011 MacBook Pro. Perhaps my computer is part of the problem, but none of these issues arise with other browsers. I am not interested in the lengthy fixes that are suggested in the existing articles on issues of using too much CPU/RAM. I thought that this new release was going to address these problems. Does anyone have any ideas? I have attached a screenshot of my activity monitor while using Firefox to browse Facebook. Thank you for your help.
Attached screenshots

All Replies (3)

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I've found a lot of threads about OSX and FF57 and excess CPU ... for me, it's made my computer basically unusable. But what I'm seeing, that none of the other threads have mentioned, is that simply hiding the application kills the CPU usage. So my average energy impact my be 100 if I leave the app visible with some windows running, but simply hiding the app causes that instantaneous impact to drop to 10 or 15. This would seem to be an issue with the rendering piece. I can verify this happens with or without hardware acceleration enabled (and I have tried all of the other suggested fixes, without luck, some of which have set my work back quite a bit). To help debug this problem, let us know if hiding the app affects CPU/energy usage.

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Hello...thanks for your response. I am not too familiar with hiding an application, but from what I can tell, this is something that you do when you are not using an app. My problems occur when I am actually using Firefox i.e. loading a webpage, so I don't think I could hide it if I am trying to view something via the browser. Right?

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Correct. But if you're looking for a quick fix, cmd-H (command key plus "H") will hide FF, and reduce CPU usage. Surprisingly, bringing FF back into the foreground (e.g. clicking on the FF icon in your dock) doesn't cause all those resources to be used again (in my case) ... I need to revisit a few of the hidden windows (which take a second to load) before I get CPU issues. This tells me that FF is doing something very non-standard on OSX with display, and is trying to use the same code across platforms for a task that should be platform-specific.

If you can confirm this is what happens for you, it might be a lead for the FF folks trying to fix this problem. I'd be curious if I'm the only one seeing this, or if this obvious lead has been overlooked by everyone dealing with this issue.