FPS Drops on PC when moving the mouse


I am having a strange issue with FPS drops when moving my mouse in game. Quick movements left or right bring it from about 90 to like 20. I am running a 1070ti as a graphics card.

The real strange thing is that I don’t get the issues when I am holding the aim button - I can quickly cycle left and right and it holds a solid 90 fps?!

This makes me think that there is some effect that gets removed when you aim? Does anyone know what that would be? I feel like if I know what video setting is removed when aiming, I could disable/lower in settings?

I have run most troubleshooting options relating to drivers and updates ect.