I have a i7 8700, 16gb ram, and GTX 1070ti I cap fortnite at 120 fps and it runs perfectly fine, and then when I open obs, its still 120fps but its laggy and makes it kinda look like its dropping frames but its staying at 120fps and then as soon as I close it its back to being super slow, ive messed with nearly every setting on obs multiple times, can someone please help me