There are also "whole house fans" which blow air from the house into the attic at high CFM rates. Those are belt driven and due to the high velocity are really noisy.Ahh.
A ventilation fan. If that is what it is, and they are noisy, sure change them. I'm unaware of any more efficient design.
The ventilation fans can use ECM motors for variable speed control and motorized louvers rather than gravity dampers which will reduce noise some.