Funnily enough, Diablo III still has that weird stutter where it's 60fps but the animations look like they're running at 30fps, so odd. Apparently that's a common issue though. I've been playing Overwatch all day without issue on max settings so the rogue 4pin was the culprit in this case, thinking back I've had this weird hitching in Witcher 3, Overwatch, Dying Light and Mad Max and it was such a simple fix all along. I'm just glad it's sorted now, I can go back to playing Overwatch which I'm really enjoying.