If you do open too many tabs in your browser these tabs may eat lot of system resources where Mozilla is trying optimize their Firefox browser for speed with Memshrink project, we’ve covered two extensions one, Dormancy which unloads all tabs that haven’t used by you for a while and second, CleanupTabs which automatically closes unused tabs. Most of the users prefer first one over the second, UnloadTab is yet another Firefox extension similar to Dormancy unloads inactive tabs to save memory.
After installing this extension, UnloadTab treats tabs as inactive if they’re idle for 10 minutes (which you can change from extension options) and inactive tabs will be dimmed to let the user know. Any tab will be restored to original state when you click on that tab on tab bar.
User is allowed to exclude some sites on tabs to be always loaded by adding their web addresses one by one manually in “keep address loaded” field of options. Pinned tabs are pre-selected to always loaded.
From any tab context menu you can unload that tab, other tabs as well and you can always keep address loaded for the selected tab.