As others mentioned, most of the games have periodic stutters, because of their engine. Especially open world games, that stream in /constantly save assets (Far Cry games) and no HW in the world could avoid this, as the time to access and move those is always percievable. And this is quantified...
Are you by any chance using Asus's rgb control software? Aura or the aurmory?
If yes, try turning any lights off. Or better, kill the Lightservice in TaskManager and see, if the stutters persist. For better measure, kill everything asus related there.