I've been using MemoryFox https://addons.mozilla.org/en-US/firefox/addon/memory-fox/?src=search with mixed results to try and reign in firefox excessive memory use when you have more than a few tabs open. it works somewhat but is not that easy to setup. found something better not sure which worked yet, I installed both yesterday because firefox would work fine for an hour or two then grab over a gig of memory and get unresponsive and have to be terminated. MemoryRestart shows how much ram is being used so you have a little warning when it's going to get unresponsive. nothing worse than that happening in the middle of a hit. often they don't respond well to reloading and you have to start the hit over. the exact amount will vary depending on your particular setup and amount of RAM etc. RAMBack works internally. for the first time when I close a tab, the RAM is returned to the system. why this type of thing isn't built into the browsers is anyone's guess. RAMBack https://addons.mozilla.org/en-US/firefox/addon/ramback/?src=ss MemoryRestart 1.1 https://addons.mozilla.org/en-US/firefox/addon/memory-restart/?src=ss this last one gives more detailed stats on how much memory each extension is using https://addons.mozilla.org/en-US/firefox/addon/about-addons-memory/versions/ you may still want to restart every few hours. probably some similar extensions out there for chrome. I only run that when a hit needs it *http://support.mozilla.org/en-US/questions/939920