Firefox Taking Up Too Much Memory
We all know that Firefox is a memory hog. Add-ons and themes can cause these types of problems, but I also discovered from a friend of mine that the amount of sites you have visited can cause issues with memory too. This means every time you visit a different page, you can always click the Back button to go back to a previous page. Firefox keeps saving those pages in memory, thus taking up more and more memory with the more pages you visit. This can add up quickly if you have several different tabs with different histories.
With this tip I started making sure I closed my browser every few hours or so to start with a clean slate. Sometimes the simple stuff makes a huge difference.
You can easily adjust the settings to limit the amount of memory used for the page cache. And I’m pretty sure you can determine whether the paging goes to memory or hard drive.