How to connect a Seasonic SS-650KM PSU to an AsRock X470 Taichi motherboard?

Question

I'm trying to figure out how to connect a

• Seasonic 650W SS-650KM Active PFC F3 Power Supply Unit

  to a

• AsRock X470 Taichi motherboard

I connected the (16 + 10)-pin "M/B" cable to the motherboard main power socket.

On the top PSU offers additonal cables that I cannot find what to do with:

• one (8 + 4)-pin "PSU" cable
• two (6 + 2)-pin "PCI-E / CPU 8P" cables

On the top of the motherboard are two sockets:

• one 8-pin "ATX12V1" (ATX 12V #1)
• one 4-pin "ATX12V2" (ATX 12V #2)

On the motherboard, I cannot see socket to power the CPU, nor the PCI-Express slots.

Here are my questions:

• Is the PSU not adapted to the motherboard?
• Do I have to power the ATX sockets on the motherboard, and how?
• Do I simply have to left the PSU's CPU and PCI-E cables unused?

Thanks a lot.

Answer 1

Is the PSU not adapted to the motherboard?

It looks like you lost 4+4 pin CPU cable somewhere. SS-650 comes with 2 cables: 8 pin CPU and 4+4 pin CPU. Please checkout PSU box.

Motherboard wants 8 pin from first CPU cable and 4 pin from second CPU cable (4 pin from second cable won't be connected).

Please do something like:

1. Attach M/B cable to PSU (2 sockets) and than attach 24 pin cable to motherboard.
2. Attach CPU cable 8 pin to PSU and than attach 8 pin to the top socket on the motherboard.
3. Attach CPU cable 4+4 pin to PSU and than attach 4 pin to the remaining top socket on the motherboard. 4 pin won't be attached, it is ok.
4. Attach PCIe cables to video card, etc.

Do I have to power the ATX sockets on the motherboard, and how?

Every powerful things on modern motherboard are powered from 12v top sockets that are connected to 12v PSU using 8 pin or 4+4 pin cables. Ancient motherboards in 2000 years had additional sockets to power PCIe slots. Modern motherboards are more simple.

Do not forget that you can't attach PCIe 6+2 pin cables to motherboard sockets. Otherwise motherboard will burn.

Do I simply have to left the PSU's CPU and PCI-E cables unused?

Yes, You can attach only one 8 pin CPU or only one 4+4 pin CPU cable. 8+4 pin power is required for top CPU overclocking only.

PS

People can still make a great CPU overclocking with PSU that has only one 8 pin CPU cable. Use "PCIe 6+2 pin -> ATX 4+4 pin" adapter. Do not forget to check this adapter pinout with multimeter before attaching it to motherboard. Wrong adapters are very dangerous for motherboard.