Asus Z9NA-D6 - Manual (Page 53)

ASUS Z9NA-D6 2-33
11. Power Supply SMBus connector (5-pin PSUSMB1)
This connector allows you to connect SMBus (System Management Bus) to
the power supply unit to read PSU information. Devices communicate with an
SMBus host and/or other SMBus devices using the SMBus interface.
12. 4-pin Power Connector (4-pin EZ_PLUG1)
This 4-pin connector is for 5V power of certain SATA DOM (Disk on Module)
device, when using an appropriate cable. You can also use this 4-pin
connector to connect the PSU to enhance power by 12V.