We found that when we switched to a higher video resolution within OBS Studio from 800x600 to 1280x720 we started getting alerts from OBS studio about CPU over utilisation with OBS Studio accounting for over 50% of our CPU usage. We were able to find a fix for this by changing the way OBS Studio encodes the video stream.
To overcome this problem we followed the steps below. By doing so we reduced the percentage of CPU used by OBS Studio to lower than 20%
In OBS Studio go to File\Settings\Output and in the streaming section change the encoder from software to hardware.