TorBrowser memory usage tweaks
I find TorBrowser eats up a lot of RAM, mostly from Vidalia and Aurora. And because I only have 512 Mb RAM on my system I am very aware of TorBrowser's RAM load [1], I for one disable all disk and RAM caching. I don't notice a hit on Tor/Aurora speed or performance, and I believe Andrew does the same - i.e., not RAM or disk caching.
According to Mozilla [2], "browser.cache.memory.capacity" can be set to "-1" to allow Aurora to decide how much RAM to use, based upon RAM size. Or it can be set to "0" to disable, or positive integer (as Kb) of user choice. And "browser.cache.memory.enable" [3] must be set to "true", which is the case for vanilla TorBrowsers.
However, the config setting "browser.cache.memory.capacity" isn't even found in TorBrowser about:config. I have to manually create the config setting, and then set the integer (I use "0"). However, I have tested "-1" for some time, and indeed, RAM usage by Aurora is reduced, sometimes by quite a lot.
Note: To save as much RAM as possible, from TorBrowser, I also set "browser.sessionhistory.max_total_viewers" to "0" [4] and I create the config setting "config.trim_on_minimize" and set Boolean to "true" [5].
References:
[1] Due to my limited RAM, and that I like to have my non-Tor Firefox running (often at Pandora.com) whilst using TorBrowser, I not only set about:config as I explained here, but I also kill Vidalia process (which is a huge RAM hog). Thus, I wait with baited breath for the time when I can use TorButton to send NEWNYM signal to Tor, without resetting TorBrowser state and clearing all current tabs, cookies, etc.
[2] http://kb.mozillazine.org/Browser.cache.memory.capacity
[3] http://kb.mozillazine.org/Browser.cache.memory.enable
[4] http://kb.mozillazine.org/Browser.sessionhistory.max_total_viewers - Caveat: this setting, when set to "0", affects back/forward browsing speed.