Is there a way to give an actor a higher priority than others?

Is there a way to give an actor a higher priority than others?
For example, on older hardware where everything runs slowly, I would be nice to give the main actor (ship/character) higher priority so it runs smoother etc.
For example, on older hardware where everything runs slowly, I would be nice to give the main actor (ship/character) higher priority so it runs smoother etc.