On a related note, in my own experience and opinion, the RPM rating of a motor or pump usually has no correlation at all to its noise level or power. It all depends on how the motor is designed and how the pump impeller and intake/outlets are engineered. For example, we just replaced our bathroom vents in our guest and master baths. The originals were cheap builders grade vents with paddle style fans and shaded pole motors. They spun like crazy and made a lot of white noise, but moved barely any air at all. To replace them, we put in Panasonic units that are much larger, with large squirrel cage blower wheels, and while they don't spin quite as fast and they're nearly silent, the air coming from the outlet in the roof is about the same as the air volume a dryer would produce. It's all in the design of the motor and the application it works with.