Open Window Settings and search for "Graphics Settings". Select "Classic App" and browse to C:\Program Files\obs-studio\bin\64bit\obs64.exe (or wherever you have installed OBS). Click "Options" (
example screenshot).
If you want to use display capture to capture your screen / desktop, select "Power Saving".
If you want to use game capture to capture a game or possibly use a hardware encoder, select "High Performance". You should only use Display Capture if you need to capture Windows stuff such as desktop and start menu. Otherwise use Window/Game/Video capture etc to build your scene. If you go that route, make sure Display Capture is not in the same scene as Game and Window Capture.
You should also do the following:
1. To ensure that OBS Studio has the hardware resources it needs for realtime streaming and recording, we recommend disabling the "Game DVR Background Recording" feature via
these instructions.
2. One of your audio devices has a sample rate that doesn't match the rest. This can result in audio drift over time or sound distortion. Check your audio devices in Windows settings (both Playback and Recording) and ensure the Default Format (under Advanced) is consistent. 48000 Hz is recommended.
OBS Sample Rate:
48000 Hz
Microphone (High Definition Audio Device):
44100 Hz
Speakers (High Definition Audio Device):
48000 Hz