ASROCK G31M-GS Mode D'emploi page 19

Though this motherboard provides 4-Pin CPU fan (Quiet Fan) support, the 3-Pin
CPU fan still can work successfully even without the fan speed control function.
If you plan to connect the 3-Pin CPU fan to the CPU fan connector on this
motherboard, please connect it to Pin 1-3.
ATX Power Connector
(24-pin ATXPWR1)
(see p.2 No. 6)
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 Connector
(4-pin ATX12V1)
(see p.2 No. 28)
ASRock G31M-GS / G31M-S Motherboard
Pin 1-3 Connected
3-Pin Fan Installation
12 24 Please connect an ATX power
supply to this connector.
1 13
20-Pin ATX Power Supply Installation
Please note that it is necessary
to connect a power supply with
ATX 12V plug to this connector
so that it can provides sufficient
power. Failing to do so will cause
the failure to power up.
12 24
1 13
1 9 1 9 1 9
1 9 1 9