R730XD Exessive Fan Speed

Got a dell R730XD and for some reason, the fans are running at ~50% PMW and making a lot of noise. and most likely filling everything with dust faster than it needs to. the air is coming out cool to the hand at the back of the chassis.

Also, we've got another R730XD running right above this one and the fans are completely quite on it. what's triggering the excessive fan speed on this machine? I've included a picture of the fans on the issue machine. Any help would be appreciated.

Jared