Question Motherboard Power Connection - Wrong Cables?

[raywindows]

I am trying to connect a Corsair RM 750x to a MSI MPG Z390M Gaming Edge AC motherboard. One of the motherboard’s power connector is an 8 pin + 4 pin. The power supply came with 2 8 pin cables and 2 6 pin (+ 2 pin) cables. How does this work?

I have a Core i9-9900K 3.6 GHz 8-Core Processor.

Did I order the wrong power supply? As best I can tell the entire line doesn’t come with the needed cable?

 

[viperdg]

Most motherboard only have 2 power connectors. The main connector is a 24 pin connector and the CPU power is usually an 8 pin connector. The CPU connector should be 2 4 pin plugs. The 24 pin one is a just 1 solid plug.

 

[raywindows]

The MPG Z390M has a 24 pin connector and a 8 pin connector right next to a 4 pin connector. The 8 Pin connector is labeled CPU power 1 and the 4 pin is labeled CPU Power 2. I don't have anything that fits the 4 pin CPU Power 2

 

[viperdg]

Okay. Sounds like in effect that is 3 ATX 12V power plugs. Must be because the 9000 CPUs use more power. I am pretty sure the 4 pin power connector is optional use for extreme overclocking. Maybe somebody can confirm that. The cable with 2 4pin plugs should be plugged into the 8 pin connector. That will supply adequate power for your CPU.

 

[TJ Hooker]

Your PSU has two 4+4 pin connectors (EPS12V). Connect one of them to the 8 pin motherboard header, and half of the other to the 4 pin header. Do not plug a 6+2 pin connector (PCIe) into your motherboard.

 

[DSzymborski]

And when TJ says do not, he really, really means do not. If you manage to stuff the 6+2 pin connector in the wrong place, that might be the end of your motherboard/CPU.

 

[raywindows]

I do have 2 cables with 8 pin connectors. I can plug 1 cable into the 8 pin connector. There is no room to plug the 8 pin into the 4 pin connector + it doesn't fit.

I've seen pictures of a 12v 4 pin plug but I have not been able to find a power supply that says it comes with such a cable.

Is there another power supply that comes with the correct cables? I cannot tell by the pictures of the cables that come with most power supplies.

 

[raywindows]

Do I need to buy a cable like the one pictured in the link below? This cannot be the only motherboard like this, how do others power it?

https://www.lifewire.com/atx-4-pin-12v-power-connector-pinout-2624579

 

[viperdg]

Like has been said don't even think about trying to put that 6 pin PCIE power plug in that 8 pin connector. The 8 pin ones are however ATX 12V power plugs. Are they labeled if so if they infact say ATX 12V on them that will assure you they are the correct ones. Those should work in the 8 pin connector. The 4 pin connector requires a split plug which is just an 8 pin connector divided in 2. If you want to use it although I am not sure if it is required you could just order a split plug cable. Your PSU did not come with a cable that has 2 4 pin plugs on it.

 

[TJ Hooker]

I do have 2 cables with 8 pin connectors. I can plug 1 cable into the 8 pin connector. There is no room to plug the 8 pin into the 4 pin connector + it doesn't fit.

The 8 pin EPS12V connector should be able to be separated into two 4 pin connectors.

 

[raywindows]

The 8 pin cables I have do not have connectors that come apart. I would need to carefully saw the connector apart into 2 pieces. So I guess I would need a different power supply that came with 2 8 pin connectors that can be separated.

Alas upon further searching the internet the extra 12 volt 4 pin connection may not be necessary. In all the reviews and system builds I've seen with this board nobody mentions the power supply and how to connect it to the motherboard.

I'm going to try it without connecting anything to the 12 volt 4 pin connector and hope it works.

 

[TJ Hooker]

Yes, you should be fine with just the 8 pin connected. It's strange that all specs/literature for the RM750x would refer to them as 4+4 pin connectors if they're actually solid 8 pin connectors.

 

[viperdg]

That PSU does infact come with a 4 +4 CPU cable. Check through your cables again.