Apparently, in order to stop the stupidly broken in-memory cacheing, you can add the following to your user.js file in your firefox profile:
// Specify the amount of memory cache
user_pref(“browser.cache.memory.enable”, false);
user_pref(“browser.cache.memory.capacity”, 8196);
I turn it off, then force it to 8MB just in case. Whoever wrote that code either riddled it with memory leaks or just has a broken notion of knowing when memory is running low (read: my machine and those of other people swap themselves to death with firefox, just like good old bloatzilla always did – which is why it got its very own oom killer policy module).
I wrote a quick hack for kswapd to send events on low memory that I’ll clean up and push out but that’s a heavyweight way to fix this bug. Anyway, I love the way they describe this hack on their FAQ pages. You need to refer to 2 other pages just to know where the user.js file should be.
Jon.
You could, of course, just wander to about:config and change the settings there.