Just a quick note on how to reconfigure fan speeds on an ASRock C2750D4I (and similar) board without rebooting into BIOS.
Changes made this way should be kept over reboots but will be lost on powercycle (stored in volatile IPMI memory).
ipmitool raw 0x3a 0x01 0x(AA) 0x(BB) 0x(CC) 0x(DD) 0x(EE) 0x(FF) 0x00 0x00
AA: CPU_FAN1
BB: CPU_FAN2
CC: REAR_FAN1
DD: REAR_FAN2
EE: FRNT_FAN1
FF: FRNT_FAN2
0x00 smart fan(bios configured)
0x01 stoped fan
0x02 lower rpm value
......
0x64 max rpm value
