CPU Usage for Orbus increases while headset is inactive

Not sure why this would be a thing. If I am playing Orbus it’s CPU usage on my Skylake i-7 is ~24%? When I take off my headset it skyrockets to 40-46%.

Also, not completely related. Why do raids lag with all class ability graphics turned off? Identically in Highsteppe, there is no lag. Am I constantly keeping track of the movements of every monster on the map behind buildings or something, etc?