May i know do you have any log from your server which showing why it spend so much resources?

By the way, what i can think of is most likely is Easysocial polling request caused used much resources on the site.

Because it will send a request to your server every 2 second in order to check whether the current logged in user got any new system notification/friend/conversation during this period of time.

Perhaps you can try extend this polling interval from backend setting and see how it goes, you can refer on my attached screenshot below.