How to connect the power supply to the motherboard

If you’re not a regular PC builder, it can be intimidating to see the profusion of tangled wires inside the CPU case. However, it is much easier than it looks to assemble and connect the power cables to the motherboard. You just have to find the right ports and that’s it.

It is obvious that the material requires energy to function. But electricity is not directly supplied to them. Most of the essential hardware components are built into the motherboard with circuit boards between them. The motherboard acts as a bridge to power several internal hardware of a computer.

Only the CD drive, hard drive, and some other hardware are powered directly from the power supply. For others, you must attach the power connectors to the motherboard and connect the components to the respective port on the board.

Thanks to this complete guide, we will learn how to connect the power supply to the motherboard.

How to connect the power supply to the motherboard?

When you take the PSU or PSU out of the box, you will see a number of wires with connectors on the end. Each of the connectors is intended to power different equipment. It is quite confusing to find the right one for each of them.

However, in the messy jungle of wires inside the case, the hardware makers gave us a slight advantage. Power connectors can only be attached to ports one way. That is, if you connect the wires the wrong way, it won’t fit and you know how to flip it.

So, let’s start connecting the power supply to the motherboard step by step, organizing a set of screwdrivers and the will to do the job.

Assembling the power supply unit to the case

The first thing to do is to place the PSU in the CPU case. Most cases have an empty box-like space at the top to hold the power supply. If you have modified your system and bought a custom enclosure, then you will need to look at its manual to find the place.

You can follow the instructions given below to assemble the PSU to the case.

  1. Insert the power supply from inside the case.
  2. Arrange it correctly to align the screw holes of the device to that of the case.
  3. Use the screwdrivers to tighten the nuts.
  4. You will see a wire harness on the other side which consists of a 20 (+4) pins power cable, 4 (+4) pins CPU power cable, 6 (+2) pin PCIe connector, one SATA connector, and a Molex connector.power connectors 1

Now that you have successfully assembled the PSU, let’s move on to connecting the cables.

Connecting the 20 (+4) pin motherboard power connector

This cable is one of the largest connectors and provides the juice needed to run all of your motherboard and its components.

The reason we write pin 20 (+4) is that the connector has a larger part with 20 pins and another with 4 pins. The reason behind this is to facilitate old motherboards which only had 20 holes to insert the pins.

atx cable 1

Since this is the biggest port on the motherboard except for RAM and the graphics card slot, you shouldn’t miss it.

Let’s see how you can install the connector on your motherboard.

  1. Find the port that is mainly at the upper right end by placing the assembled board upright in front of you.
  2. Insert the 20-pin connector into the port so that its key aligns correctly with it and it enters the port without any considerable force.
  3. Insert the smaller 4-pin part in the same way. You can also do the process in reverse.

Now let’s see how to connect other power pins to the motherboard.

Connecting the 4 (+4) pin CPU power connector

Another cable you will find at the output of the power supply is a 4 (+4) pin CPU power connector. This cable provides power to run your processor.

This connector is also split into two parts with 4 pins equally distributed on each of them. You can use either only the single 4 pin part or both parts according to the needs of the motherboard. Some motherboards with advanced features require more power. The power supply designed for these cards even consists of two 8-pin connectors.

4+4 pin motherboard

But it does not matter the size of the connector. The process to connect it is the same. Here’s how.

  1. Find the port for this connector which is usually near the processor or fan covering the CPU.
  2. You will see a port with 4 or 8 holes. Sometimes there may also be two 8-hole ports.
  3. Insert part of the pin by aligning its key.
  4. Follow the same for the remaining part if your motherboard requires both.
    connection to processor power supply

Your processor can work with only one 4-pin connector even though it has a port that requires 8 pins. However, it may malfunction due to insufficient power and I would not recommend doing so.

But for the high end board with two 8 pin requirements, you can just pop one in and it will do the job. You need to insert the rest if you want to do additional things such as CPU overclocking.

Now that you’ve powered up your motherboard and processor, let’s move on to the other connectors.

Connecting the PCIe 6 (+2) pin connector

Previously, we didn’t have heavier programs and worked with zero or lower capacity video cards. These graphics cards could power themselves by taking the elixir directly from the motherboard.

However, as our desire increased, the capacity and therefore the power required for the video card increased. The graphics card we use today may require power directly from the PSU. For this reason, PSU manufacturers provide us with a removable 6-pin and 2-pin cord to power the video card.

6 pin connector

Similar to the processor, the power requirement for the graphics card also varies by type. Some require 6 pins while others require 8 pins to run it. Here’s how to connect either to the correct port.

  1. Find the port behind your video card.
  2. Insert the 6-pin cable into the port.
  3. If necessary, do the same to connect the 2-prong cord there as well.pcie connection
  4. If your graphics card header has two 8-pin connector requirements, you should check if your power supply provides it before purchasing.

Also, there may be two different connectors, one for the video card and another for the CPU, having 8 pins on both. To differentiate which belongs where you just need to look at the structure. The connector for the processor is split in the middle, and the rest mostly have a split into 6 and 2 separate pins.

Let’s see what job the remaining cables have on your computer.

Connecting the SATA connector

Among the hardware in your computer that requires direct power from PSU, HDD, SSD, CD/DVD drive, etc., there are some. These devices use the mentioned SATA connector to receive power.

SATA cables

If you have learned how to connect other connectors, it is just as easy. Here’s the way to do it.

  1. Find the header on the back your HDD or SSD or required hardware.
  2. Insert the SATA connector into the header in an orientation so you don’t have to force it.
  3. The SATA connector also fits in a single path, making it easier for you to recognize the correct path.sata-connection

These cables are optional to use except for HDD or SSD. You usually get at least 2 SATA connectors. You can leave the others untouched if you don’t have extra hardware that needs them.

If you have become perfect for connecting the SATA cable to different hardware, let’s discover its older brother, the Molex connector.

Molex connector connection

Do you remember old hard drives that had a number of pins behind them? You must also have immediately thought about the cable to power the hard drive through the power supply. This cable is the Molex connector.

These days, the Molex connector doesn’t have much use. However, PSU manufacturers like to be cautious in supplying these cables per unit. If some users are still using the old hard drive and motherboard, it is better to have at least one Molex connector in the power supply.

molex connector 1

It works the same way as SATA cables. SATA cables can be considered as the replacement of the Molex connector.

Let’s see how to recognize the Molex connector and how to connect it.

  1. Find a connector with 4 holes on it with no extra parts.
  2. It’s the simplest of all that powers HDD or CD/DVD drives or sometimes a case fan.
  3. You will see a slightly curved surface and a full rectangular surface on the connector.
  4. Find a port on the back of the respective hardware.
  5. Maintain the orientation of the connector so that it enters the port easily.
  6. It can also be connected only one way like the other connectors.

There may be an additional small 4-pin connector coming out of the PSU. This pin is similar to a Molex connector but only smaller. This pin is there to power a floppy drive.

The pin connection process of an FDD is similar to other connectors. Most systems today do not have an FDD and this connector is now practically useless.

You have now learned how to connect all power cables to different parts of a motherboard with hardware. If you manage the cables neatly with zip ties or some process, you can easily assemble all the connections for your computer.

Alan A. Seibert