Firefox using a lot of memory? Well, according to Firefox, it is a function not a problem. Huh? They say firefox will use a lot of memory to save those pages you had already browse into the memory so that when you click back you can get the pages quickly or when you are simply doing multitasking, opening many tabs, running many addons. Anyway, you can always try these to control firefox from using too much memory.
Follow these simple steps to get your Firefox memory usage under control.
But remember, these configuration changes are a trade-off between internet browsing speed and memory usage. They are most useful if you are multitasking and need Firefox to be less of a memory hog while using other applications.1. Type “about:config” into your address bar to access the hidden configuration options for Firefox.
2. Right click on the page and choose New then Integer and create an integer called browser.cache.memory.capacity and set it to a low number. This controls how many kilobytes of memory are used for the browser’s cache. Try make it 80% of your RAM.3. Set browser.cache.disk.capacity to between 5000 or 15000.
4. Right click on the page and choose New then Boolean and create a boolean called config.trim_on_minimize and set it to true. Now when you minimize the window it will free up memory.
128MB to 512M -> 5000.
512BM to 1GB of RAM -> use 15000
5. Set network.prefetch-next to false.
6. Set browser.sessionhistory.max_total_viewers to 3.
Hopes this helps!
Sources : kb.mozillazine.org