BuddyPress.org

I use the Cometcache plugin, the paid version it has a great feature called loggedin user caching.It creates a user specific cache for each user that is logged in and refreshes the cache when a user has an interaction with the site like posting an update or making a friend request. .The downside is the cache can grow quite big if you have a lot of users but you can choose to clear the cache when they log out. https://cometcache.com/features/