Want to quiet those fans on a R740XD?
Make sure to use iDrac firmware 3.30.30.30
// Enables Manual Fan Control
ipmitool -I lanplus -H $IP -U root -P $iDracPass raw 0x30 0x30 0x01 0x00
// Sets all fans to 10% change the last 2 #s to anything you like. 0x05 for 5% etc.
ipmitool -I lanplus -H $IP -U root -P $iDracPass raw 0x30 0x30 0x02 0xff 0x10
// Command to show Sysinfo/ FAN speeds.
ipmitool -I lanplus -H $IP -U root -P $iDracPass sdr list full