MSI B550 GAMING GEN3 AM4 ATX Motherboard - Manual (Page 38)

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CPU_FAN1, PUMP_FAN1, SYS_FAN1~4: Fan Connectors
Fan connectors can be classified as PWM (Pulse Width Modulation) Mode or DC Mode.
PWM Mode fan connectors provide constant 12V output and adjust fan speed with
speed control signal. DC Mode fan connectors control fan speed by changing voltage.
The auto mode fan connectors can automatically detect PWM and DC mode.
You can control fans in
BIOS> HARDWARE MONITOR panel. It allows you to set DC
or PWM to your fan type. Check the Smart Fan Mode , the fan speed will change
according to the CPU or system temperature. Uncheck the Smart Fan Mode , the fan
will spin at maximum speed.
⚠
Important
Make sure fans are working properly after switching the PWM/ DC mode.
CPU_FAN1
SYS_FAN2
SYS_FAN4
SYS_FAN1
PUMP_FAN1
SYS_FAN3
1
PWM Mode pin definition
Pin Signal Name Pin Signal Name
1 Ground 2 +12V
3 Sense 4 Speed Control Signal
DC Mode pin definition
Pin Signal Name Pin Signal Name
1 Ground 2 Voltage Control
3 Sense 4 NC
Fan connector specifications
Connector Default fan mode Max. current Max. power
CPU_FAN1 PWM mode 2A 24W
PUMP_FAN1 PWM mode 3A 36W
SYS_FAN1~4 DC mode 2A 24W