ASROCK 770 EXTREME3 User Manual page 22

Though this motherboard provides 24-pin ATX power connector,
it can still work if you adopt a traditional 20-pin ATX power supply.
To use the 20-pin ATX power supply, please plug your power
supply along with Pin 1 and Pin 13.
ATX 12V Power Connector
(8-pin ATX12V1)
(see p.10 No. 3)
Though this motherboard provides 8-pin ATX 12V power connector,
it can still work if you adopt a traditional 4-pin ATX 12V power
supply. To use the 4-pin ATX power supply, please plug your
power supply along with Pin 1 and Pin 5.
Serial port Header
(9-pin COM1)
(see p.10 No.28)
HDMI_SPDIF Header
(3-pin HDMI_SPDIF1)
(see p.10 No. 31)
20-Pin ATX Power Supply Installation
Please connect an ATX 12V
4 8
power supply to this connector.
1 6
4-Pin ATX 12V Power Supply Installation
This COM1 header supports a
RRXD1
DDTR#1
serial port module.
DDSR#1
CCTS#1
1
RRI#1
RRTS#1
GND
TTXD1
DDCD#1
HDMI_SPDIF header, providing
SPDIF audio output to HDMI VGA
1
GND card, allows the system to
SPDIFOUT
+5V
connect HDMI Digital TV/
projector/LCD devices. Please
connect the HDMI_SPDIF
connector of HDMI VGA card to
this header.
2 2 2 2 2 2 2 2 2 2
12 24
1 13
4 8
1 6