OBS is open game lags feels not smooth

[Blizzarts]

So i recently startet streaming on twitch and i dont have a VERY good pc but the problem is that when i only open obs ( i dont stream or record somthing) my games strat to lag or feel not smooth but when i look at the fps ingame there over 500 but still feel unsmooth.

Specs:

Ryzen5 2400g
GTX 1660 super
16 gb
Corsair Vengeance RGB PRO
500 gb ssd
1tb hdd