How to fix firefox memory leak and slowness on the Mac

As a developer, I run Firefox all day long. Then I began to notice that Firefox would get progressively slower, to the point where it wouldn’t want to move anymore. So here is how you can diagnose and fix the problem to make Firefox faster:

1) open “Activity Monitor”

activity monitor firefox

2) Notice how on mine Firefox is reaching 1GB of memory?

3) Close Firefox and whatever else you think is being a memory hog.

That’s it. It will be faster. I recommend doing this 2-3 times a day.

  • Nick

    By the title of your post (and it’s high search rank in my google search) I was hoping you actually had a fix for Mac Firefox. But restarting often is not a solution. Besides, after just 1 hour with 3 tabs open (1 being Gmail) the memory got up past 600MB and is concerning a far amount of CPU! I don’t want to have to restart hourly.

    It makes me sad that I have to use Chrome and their inferior dev tools since I just can’t put up with such a slow, bloated browser any more.

  • Anonymous

    This is actually funny…in a sad, sad way. I thought it was Google Toobar but it wasn’t. Still no clue what causes this.

  • So you are actually telling us that how to check the memory usage of a software in Activity Monitor. This is not a fix.

  • This is SO not a fix.

    But since others will probably come, as we did, at least we can give them something useful:
    • GeekTool to show Firefox memory on the dashboard, so it’s easy to keep an eye on, and
    • Restartless Restart to put a button in FF’s toolbar to make restarting effortless.