ATX12V 8pin motherboard connection help

[Zenara25]

EPS/ATX12V CPU Cable. I bought a new 1155 motherboard and have a question about this connection that attaches to the motherboard 8 pins. I have a Corsair 400Watt CMPSU-400CX power supply.

They do fit into the motherboard but I'm worried about turning it on because the square and rounded tops do not match up. Don't want to fry my new board. Is this safe? Or do I need a new PSU?

http://www.corsair.com/power-supplies/non-modular-psus/builder-series/builder-series-cx400.html

If this should go in the CPU or motherboard section please feel free to move. Wasn't sure where to ask this one.

 

[dma0991]

The 4+4 pin EPS goes to the motherboard while the 6+2 pin PCIE goes to the GPU. I hope you are not plugging it the other way around. If it fits in to the socket without much force and it latches to the socket then you won't have any problems.

 

[VirtualLarry]

I'm concerned that you say the square and round pegs don't match up. They should match.

If your PSU has a 4+4 EPS12V/ATX12V connector, then use them both if your mobo has an 8-pin, otherwise, use one half of it if your mobo has 4-pin. It should fit.

If the PSU has a 4-pin, and the mobo has an 8-pin, then it will fit into half of the connector. I don't remember which half off of the top of my head though.

Do NOT mix up the 4-pin connector that is part of the 20+4 ATX main power connector, with the EPS12V/ATX12V 4+4 connector.

 

[BoomerD]

http://www.playtool.com/pages/psuconnectors/connectors.html

Pay careful attention to the connectors. The Pci-E and EPS12v connectors may LOOK similar...but they are NOT interchangable.

 

[Zenara25]

Thanks everyone. I decided to try it and everything worked after I figured out I had the reset and power case connecters swapped I was about to pull out the flat head screwdriver trick to manually try to power on (bypassing the case connectors). Sure made me nervous for about 15min though.

My old P35 board had only a 4pin cpu connection (there was a second 4 pin that wasn't being used almost attached to it-this is the other one I used to make an 8pin on the 1155 board) and the square/square with rounded edge on the PSU connector was exactly the same as on the board. Maybe the new 1155 slightly changes that? But it still fits and works so I'm happy.

 

[Yellowbeard]

I'm concerned that you say the square and round pegs don't match up. They should match..

Actually this is not correct. The shape of the pins is not critical on the 12v EPS plug and they are designed to allow the greatest compatibility with both 8 pin and 4 pin MOBOs.

 

[Nate650]

Actually this is not correct. The shape of the pins is not critical on the 12v EPS plug and they are designed to allow the greatest compatibility with both 8 pin and 4 pin MOBOs.

Bingo. I know this is an old thread but wanted to add to this in case someone comes across the same problem.

For a power supply that has a 4+4 pin 12V CPU connector, sometimes the secondary half may have 4 pins that are all semi-rounded. In such cases, it may seem like this doesn't fit in the second half of the corresponding 8-pin connector on the motherboard because 2 of the pins will be square. However, the 4 semi-rounded pins can and should be plugged into the 2 square and 2 semi-rounded pins on the motherboard connector. I was having an issue where the computer was rebooting under heavy load and it was due to insufficient power the CPU due to only the 4 pins being plugged into the motherboard. The issue was resolved after plugging in both 4-pin connectors.