By default, it will going to 100% which consume more watt and noises. To adjust your Dell R730RD Poweredge fan speed, you can do this step.
1. Get the IPMI ip address, username and password
2. Install the IPMI client https://www.dell.com/support/home/en-id/drivers/driversdetails?driverid=m63f3&driverid=m63f3
3. Open your powershell and execute these command
ipmitool.exe -I lanplus -U username -P password -H 192.168.18.7 raw 0x30 0x30 0x01 0x00
This command will enable the option to modify the fan speed. Next you can add this example to go 80% of speed
ipmitool.exe -I lanplus -U username -P password -H 192.168.18.7 raw 0x30 0x30 0x02 0xff 0x50
Or you can change the last two alphanumeric with the conversion from