The system has X cores, but Corona is configured to use only Y - rendering will not run at optimal speed.
This message appears whenever you reduce the number of rendering threads by more than two using the # of threads option in Render Setup > System > System Settings. It acts as a precautionary alert to ensure the change wasn’t made unintentionally or set to an incorrect value.
Solutions:
- Make sure you do not reduce the number of rendering threads more than necessary.
- In case you wish to keep your settings, you can dismiss this error by clicking "Ignore similar messages” button in the Error Messages window.