If you're having a technical issue with your game or believe you have found a bug, please report on the Official Forum as we no longer have sub forums for this on Steam. https://forum.deadbydaylight.com/en/
For any technical issues that you are having with the game (this looks to be a graphical error with your hardware/drivers), please go to the Technical Sub forum on the Official Forum for assistance: https://forum.deadbydaylight.com/en/categories/technical-issues
With that set up you shouldn't be having FPS drops at all. Can you give more information about when it's occurring, any particular maps etc. Video would be really helpful if you could record it.