This setting is only available for Windows users with NVIDIA video cards. You will need to be using the latest NVIDIA driver and Control Panel software available. Head over to NVIDIA's website to check for the latest drivers for your computer and update if necessary.
Once you have updated the NVIDIA Control Panel, right-click on your desktop. You should have an option for NVIDIA Control Panel in the right-click menu. If not, click on Start and search for "NVIDIA Control Panel".
In the NVIDIA Control Panel, select "Manage 3D Settings" from the list on the left. It may take a few seconds for the next screen to load. Scroll down in the Global Settings options to the bottom of the list. You should see an option called "Threaded optimization". Change this option to "Off" and then click Apply.
Turning this setting off fixes microstutters in the output rendering for some users. We have found that it improves performance on several of our computers internally as well. Not all users will benefit from this setting, but turning it off won't have any negative impact on the performance of the program.
It does not appear to have any impact at all in ProPresenter 5, it will only impact ProPresenter 6 users.