Firefox + OS X = CPU and RAM (chomp… chomp… chomp…)

Firefox on my Powerbook is really starting to give me the sh#*s. I’ve ensured that I have as few extensions as I can live with. I think I have around 15, including Google Toolbar, Adblock, Adblock Filterset.G Updater, coComment, FireBug, FasterFox, PDF Download, Web Developer, Sage,, CustomizeGoogle, Update Notifier, Restart Firefox, Download Statusbar, Linkedin Companion and the new Google Browser Sync).
As it stands, every time I shift tabs, or try to load a page, the thing goes into beachball madness and the CPU maxes out for anything up to 30 seconds. Frankly, I’m not delighted about it. I’m pretty certain that it’s one or more of the extensions I’m using, but I can’t isolate which one.

Anyone out there have a clue about which one is likely to be the culprit? I reckon I can live with a few less extensions if I can get Firefox to work properly.

7 Replies to “Firefox + OS X = CPU and RAM (chomp… chomp… chomp…)”

  1. Hey Stephen,
    I’m using the same config and noticed the exact same thing. I think it’s a combination of:
    – computer getting older (is there an equivalent of defrag on mac? Mine is REALLY getting slower and it seems to come from the hard drive)
    – firefox updates. Each new version seems slower
    – tabs. I open 7 now on start (what a great feature btw…) and it’s bloody slow…
    I hope a new macbook (and a new firefox version) will fix that…

  2. Hm, if you have problems then just disable all the extentions. Yes, realy. After that you will soon find out which ones you realy need, and then you can enable them one at a time. ok, you probably going to reanable half of them straight away but then again at least you get to fine which one is causing you problems…

    I had a criminal 51 extensions installed (well maybe a bit less – I keep on adding to them) but now only have 24 enabled. 24 ouch, must dissable some more…

  3. I’ve got a brand-spanking-new MacBook (2.0GHz, 2GB RAM) and I’m always annoyed that FF uses 30% CPU *constantly* when I have “complex” stuff open like gmail (which I leave open all day long). This causes the Macbook to heat-up more than necessary which is my main complaint.

  4. Hi,

    it’s Adblock. With Adblock disabled, Firefox chugs away happily with 2-4% CPU useage. With adblock enabled, CPU useage rises up through the roof after some time.

    And this seems OS X specific – I can use Adblock under Linux (FF2.0) fine, and Windows users don’t seem to have a problem either.


  5. Its definately Adblock Plus… I’ve been experiencing it for a couple weeks now. Still works fine under Linux, and Windows — but it actually gets worse the longer you leave the browser open. Its blocking somehow – not sure how. Does not seem to be a steady rate of CPU utilization, rather its blocking for every page interaction. I had to go through just about my entire collection of extensions before I noticed an improvement by disabling Adblock Plus :(

    Re-enabling the previously disabled extensions minus ABP did not cause the blocking to reoccur. This is a bummer really – I hope to see it solved and will follow up with the ABP author to see what I can do to isolate the problem.

  6. I experienced that if you install Noscript in addition to Adblock, it seems to get better. I haven’t had any occasions where Firefox would idle with 20-25% CPU yet since I did that.

    The downside is that you have to confirm Javascript for each site once, after installing Noscript (that’s the idea) – but that can also be a good thing, since most ads use Javscript.


Leave a Reply