OBS (Encoding X264) fails
Here are some things to try:


Switch to OBS Studio. OBS classic is no longer supported and has been replaced by the "studio" version.
Tell your OS to run OBS in "high priority" mode.
Set your encoding preset to a lower quality and/or lower FPS and/or lower definition
Use your GPU to encode (NVENC). Your CPU will no longer encode your stream and will be able to run other tasks, but it will downgrade the quality of your video.