The memory requirement increases rapidly to more than 100 mb when you surf for a long time in a firefox browser or open many tabs at a time.
Reason .........
Two effects cater Firefox's ever increasing appetite for memory.All web sites open in tabs and windows occupy memory space; this space remains occupied even after minimizing windows.Besides,Firefox also saves 50 recently visited websites in the main memory of the PC in order to facilitate quick browsing through the session history.To reduce this unnecessarily large number of saved sites.
Solution .........
Enter 'about:config' in the address bar. Search for 'browser.sessionhistory.max_entries' in the 'Preference Name' list and double-click on it to edit it.Change the default setting '50' to a considerably smaller number or even to '0' and confirm with 'OK'. When you enter '1' or '5' you can still access the last visited websites since they are still available in the RAM. Incidentally, saving the history is not affected by this setting. Thus, you can browse through as many sites as you want; you only need to wait for the renewed loading of these websites.
You can also instruct Firefox to release the memory space that is no longer in use. Simply right-click on any space in the list of configuration settings and select the context command 'New | Boolean'. Enter 'config.trim_on_minimize' and click 'OK'. Click on 'True' in the following dialog and again confirm with 'OK'. Now restart the browser.