Once your Tabs go over certain number of active tabs. There are people with hundreds of Tabs. And Safari doesn't do Tab Sleep. Instead it put those tabs in the

Once your Tabs go over certain number of active tabs. There are people with hundreds of Tabs. And Safari doesn't do Tab Sleep. Instead it put those tabs in the background as active but low priorities, works well when they fit within Memory and some paging. Stop working when it is above that. Tab Overview will also cause every single Tab to be re-rendered. Video Playing is also another problem especially with Youtube. Having Youtube Tabs opened in the background also causes memory pressure issues. On Desktop, Chrome and Firefox is so far ahead of Safari.