How to reduce Firefox (FF) memory usage?

How to reduce memory usage in Mozilla Firefox

 

Know your browser

Type about:memory in the Firefox address bar. This will show you current memory usage.

Browser history

1. Type about:config in the Firefox address bar
2. Do a search for browser.sessionhistory.max_entries
3. Double click the default value (50), change it to something lower (3, 4, 5).

Addons

1. Type about:addons in the Firefox address bar 
2. Disable unused/unnecessary/unknown addons and plugins

AdBlock Plus

If you don't have AdBlock Plus, you don't know what you are missing: The Internet without ads!!! I am not kidding! However, it was reported that AdBlock Plus increased memory usage. So, if you have lots of open tabs, you may want to disable this plugin.
I did an experiment in May 2015, and it seems is not true, or at least, they fixed this issue, since then.


Enable hardware acceleration

1. Type about:preferences#advanced in the Firefox address bar
2. Check "Use hardware acceleration when available".

Please note that in my case this creates other (font-related) problems.



Restart Firefox often

In my case it helps a lot to restart Firefox every hour.


History

Press Ctrl+H to show the 'History'. Delete all entries older than 6 months.


Install it fresh

Installing a fresh copy of Firefox will help a lot. Somebody made and experiment about this here: https://support.mozilla.org/en-US/questions/1011071





In my case, the memory consumption decreased from 900MB to 500MB.