Random thoughts, ideas and experiences

Unreasonable Firefox memory usage

I upgraded to Firefox 2.0 recently and was impressed like most other folks. Things were fine until I started noticing excessive hard disk activity as well as sluggish performance and intermittant hangs.

Task Manager showed Firefox using ridiculous amounts of memory, more than 300MB with several open tabs in multiple windows. Considering my wife and I use separate windows for our work, quitting and restarting every day is not convenient since Firefox only restores the session of the window that was closed last.

A few searches on Google led to the following page on the Mozillazine knowledge base; basically, a list of add-ons known to cause all sorts of trouble for Firefox. Comparing my list of installed add-ons with the page led to the following short list of potential culprits:-

I was only using Google Toolbar to auto-fill my forms so it wasn’t hard to uninstall it. As for IE Tab, I installed the recommended alternative IE View Lite which is a sufficient solution. Having IE embedded into Firefox is a nice to have but not essential.

From that point on, Firefox memory usage has stayed under 100MB for the most part. After several days of usage spanning multiple tabs, windows and websites, it gets to 140MB which is pretty reasonable compared to the original 300MB.

Here’s what my add-on list looks like now:


There’s more tips for reducing memory on this Mozillazine page if you are interested in further improvements.


Filed under: Tips

5 Responses

  1. Fahad Fateh says:


    here is a link that would further help you bring down the FF mem usage.

    Hope it helps.

  2. klaus says:

    The easiest way around is updating to ff 3, beta 5. No more memory leaks.

  3. zone alarm says:

    Good info and well presented, for more quality free info on pc security related issues have a look here.

  4. Nirose says:

    Hey guys use the firefox ultimate optimizer .It drastically decreases the memory usage of the Firefox.Available at

  5. Rita says:

    Ya guys using the Firefox ultimate optimizer really decrease the memory usage on Mozilla but the CPU stays the same.,

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