0. Record to MKV
1. The version of Windows you are running has a limitation which causes performance issues in hardware accelerated applications (such as games) if multiple monitors with different refresh rates are present. Your system's monitors have 2 different refresh rates, so you are affected by this limitation.
To fix this issue, we recommend updating to the Windows 10 May 2020 Update. Follow these instructions at
https://blogs.windows.com/windowsexperience/2020/05/27/how-to-get-the-windows-10-may-2020-update/ if you're not sure how to update.
2. Your GPU is maxed out and OBS can't render scenes fast enough. Running a game without vertical sync or a frame rate limiter will frequently cause performance issues with OBS because your GPU will be maxed out. OBS requires a little GPU to render your scene.
Enable Vsync or set a reasonable frame rate limit that your GPU can handle without hitting 100% usage.
If that's not enough you may also need to turn down some of the video quality options in the game. If you are experiencing issues in general while using OBS, your GPU may be overloaded for the settings you are trying to use.
Please check our guide for ideas why this may be happening, and steps you can take to correct it at
https://obsproject.com/wiki/GPU-overload-issues
3. In Windows 10 versions 1809 and newer, we recommend that "Game Mode" be enabled for maximum gaming performance. Game Mode can be enabled via the Windows 10 "Settings" app, under Gaming > Game Mode
4. Run OBS as Admin