Double Your Internet Browsing Speed
Firefox RAM Memory Bug. Lets get it straight. It’s not a bug. It’s part of the cache feature. This ‘feature’ is how the pages are cached in a tabbed environment.
To improve performance when navigating (studies show that 39% of all page navigations are renavigations to pages visited less than 10 pages ago, usually using the back button), Firefox implements a Back-Forward cache that retains the rendered document for the last five session history entries for each tab.