For Firefox I am using an extension called auto tab discard (https://addons.mozilla.org/en-US/firefox/addon/auto-tab-discard/ https://addons.mozilla.org/en-US/f

For Firefox I am using an extension called auto tab discard (https://addons.mozilla.org/en-US/firefox/addon/auto-tab-discard/ https://addons.mozilla.org/en-US/firefox/addon/auto-tab-disc...). It will suspend tabs from memory that have not been opened for a given time but you can easily open them again by pressing the tab. You can also whitelist some domains to prevent them from being suspended. Give it a try. There is also the great suspender for Chrome.