Use a 32-bit version instead of 64-bit. First, Javascript interpreters use lots of pointers, and doubling the size of every pointer adds up. Second, this will l

Use a 32-bit version instead of 64-bit. First, Javascript interpreters use lots of pointers, and doubling the size of every pointer adds up. Second, this will limit memory usage of each process to 4GB max, maybe 3 or even 2. Then, lower your cache sizes. Modern browsers (and OSes) won't let your RAM sit empty if they can fill it with data that you might use later. Check about:cache. If you want, set browser.cache.memory.capacity to an actual value instead of -1. It's in kilobytes, so multiply accordingly. http://kb.mozillazine.org/Browser.cache.memory.enable http://kb.mozillazine.org/Browser.cache.memory.enable Or disable browser.cache.memory.enable entirely. Modern browsers run different sites in different processes for security. If you're not that worried about it, you can disable this in Firefox by setting browser.tabs.remote.autostart to false. Now when a tab crashes it will kill your whole browser, but it will use less RAM. Remember to restart your browser for these changes to work. Finally, check in about:performance to make sure you don't have some extensions hogging RAM.