4-Pin PSU Connector – Is It Required for Mini Cases?

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I am trying to build a computer, placing an ASUS P8H67-I DELUXE in a custom retro Commodore 64 case.

The case is an extra small form factor which can accommodate the Mini ITX board, but it requires an external power supply, similar to the power-bricks that laptops use.

I am looking at different power supplies and like these, but I cannot figure out whether/how to power this system, because they provide a 24-pin connector, but the motherboard has a 4-pin connector as well.

Is the 4-pin connector optional or is it required? If it is required, how can I provide power for this system?

Best Answer

The 24 pin EATX power connector...

The 24 pin main power connector was added in ATX12V 2.0 to provide extra power needed by PCI Express slots. The older 20 pin main power cable only has one 12 volt line. The new 24 pin connector added one line apiece for ground, 3.3, 5, and 12 volts. The extra pins made the auxiliary power cable unnecessary so most ATX12V 2.x power supplies don't have them. The 24 pin connector is polarized so it can only be plugged in pointing in the correct direction.

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The separate 4-pin ATX 12 V that is on your board...

Older computers put most of their load on 3.3 and 5 volts. As time passed, computers drew more and more of their load from 12 volts. Before this power cable was introduced there was just one 12 volt line provided to the motherboard. This cable added two more 12 volt lines so more of the load could be shifted to 12 volts. The power coming from this connector is usually used to power the CPU but some motherboards use it for other things as well. The presence ‎of this connector on a motherboard means it's an ATX12V motherboard. For dual 12 volt rail power supplies, this connector provides the voltage referred to as 12V2. The power cable which plugs into the 4 pin connector has two black wires and two yellow wires. This cable is sometimes called an "ATX12V" cable or "P4" cable although neither of those are technically accurate descriptions.

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So there you go. What they are for with images and links.

More information us in Super User question Core i3-2100 with 65W power supply?.

Using this same PSU calculator, with the information you provided CPU, two sticks DDR3, one SSD flash drive) I came up with 146 watts required. So, the Pico 160 watt mini PSU should be enough.

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