Game Mode: On |Off
Turning this “On” While using OBS will give OBS rendering performance, and can possibly loose Frames (FPS) in your game. Your stream will be smoother without encoder overload, but your game may suffer. Turning this “Off” will keep all your FPS in game, but OBS may have encoder overload issues.
Windows Start >> Settings >> Gaming >> Game Mode

Hardware-accelerated GPU scheduling: On | Off
Reduce latency and improve performance. OBS says to turn this “Off” due to being experimental, and could cause issues with streaming. I personally have not noticed any issues.
Windows Start >> System >> Display >> Graphics Settings
