Loss of Power after New Fan Clutch

You didn't notice it because the old clutch didn't work well to start with and was worn out. These units lose 5~10% of their efficiency each year as they age. You probably hear it roar in the morning now and when ever it has cooled of some - that's a good thing and a sign it's healthy.
Ram has changed the logic of how and when these fans actuate. They keep the eng cooler and temp more consistent. You will also find your AC works better and has an easier life (lower pressures) during stop and go traffic.
Yes, because that fan can move so much air (way more than any electric), it takes a lot of HP. The one for my diesel pulls 23 HP.
Other than the HP loss, everything about that new clutch is positive.

Scott- My buddy, who is a good mechanic told me the same thing, sounds like a healthy fan clutch...still, my old fan clutch was quieter and my truck had a lot more power, even pulling my truck up from Southern California to San Francisco.