i have the same type of issue my OBS is set to 60 fps but i twill drop to completely random numbers like 57.02 or 37.89 this happens while streaming and having my game be the foremost window. if im clicked out of the game it goes back to an even 60.00 fps. i have tried everything from updating my BIOS, drivers, changing all sorts of settings, resetting my router, and even resetting my pc. all i want to do is stream to my viewers without lag as much as possible, i dont even care abut the quality that much.