It is my experience that any mechanical component will start to make noise at some point. Better to avoid it altogether. I don't understand why you say that us

It is my experience that any mechanical component will start to make noise at some point. Better to avoid it altogether. I don't understand why you say that using a fan would make the CPU use less energy. On the contrary, the fact that a CPU requires cooling indicates that it uses more energy than a CPU which doesn't (more energy converted to heat).