Mozilla Firefox Memory/Speed Optimization

Customize Mozilla Firefox settings to use very less memory and optimize internet and start-up speed with these tips.

Mozilla Firefox is awesome, I’ve been using it for longest of time and it has grown from being a constantly crashing browser to very stable with the latest technologies and with the best of security and privacy. As it does all of these things it can use up a lot of system memory. Although Firefox has been blamed for memory leaks and instability, the latest versions are well trimmed and very very stable. There are some features we could live without or set the settings to a lower level to make Firefox use as much less memory as possible.

firefox memory speed optimizations

In this post we are going learn some configuration tricks that is going to help reduce the memory usage. In the Firefox navigation bar type “about:config” to access the inner configuration setting. Accept the “I’ll be careful, I promise” button and access the feature.

Note that these optimization are for older system with low RAM and CPU power. You might gain very little if you have a modern PC with gigs of RAM and latest processors.

Memory Optimization (Remove bells and whistle or set settings to lower):

CHANGE: browser.newtabpage.enabled -> false.Disables the frequently viewed sites and thumbnails to load

CHANGE: pdfjs.disabled  -> true. Disables the inbuilt pdf reader.

CHANGE: browser.sessionhistory.max_entries -> (17). The integer is the number of times you can go back in history

CHANGE: -> false. Stops animations for downloads

CHANGE: browser.tabs.animate -> false.  Stop browser tab animation when opening and closing a tab.

CHANGE: -> false. Disable search suggest in the search engine panel.

CREATE: browser.cache.memory.capacity (integer :102400). 102400 refers to 100 MB memory used

CREATE: config.trim_on_minimize -> (boolean: true). Trims memory when the Firefox is minimized


Internet Speed Optimization:

CHANGE: network.http.pipelining -> true

CHANGE: network.http.pipelining.aggressive -> true

CHANGE: network.http.pipelining.ssl -> true

CHANGE: network.http.proxy.pipelining -> true


Other tips:

  1. Disable add-on you don’t use often, Activate them only while you need them.
  2. Adblock Plugins use a lot of memory to run, use them only if the system can handle the overhead.
  3. Disable flash and Java loading automatically by setting them to manual activation at Add-ons manager.
  4. Search for alternative add-ons, extensions that don’t need restart to activate.
  5. Check your Firefox Health report at “about:healthreport“. If Firefox is taking a lot of time to load it may be time to reset it at “about:support“.
  6. Manage your bookmarks, remove the bookmarks you don’t need.
  7. Optimize Firefox local database with SpeedyFox.


If you have any other optimization tips we would love to hear them or comment on the configurations listed on here. I was able to get the memory usage of Firefox to around 90 MB on an old Windows XP machine without breaking anything. So please let us know in the comments

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