Dell PowerEdge 12th Generation Servers have introduced a fan speed offset setting that enables fan speeds to be increased over those calculated by the Dell Thermal Control algorithm.
Some 3rd party add in cards will need the increase system fan speed response to provide additional cooling
Fans are expected to run to cool the servers so it is not uncommon for the it run at a high speed. I recommend approach these settings with caution, this may be normal because of the state of system. Dialing down the fans could cause the server to overheat.