Whenever you are installing a PSU, you might feel a bit overwhelmed by a bunch of cables emerging out of it. Plus, the design of the connectors look so similar that it’s hard to figure out which one goes where.
It is always crucial to be familiar with the power supply connectors to ensure stable and efficient power delivery to each of the PC components. Although the available connectors vary depending upon your PSU model and manufacturer, there are some common ones you’ll always find.
In this article, I’ll be discussing the ATX power connector that supplies power to your main board and the CPU power connector that gives power to the CPU. Besides, you’ll also learn how the PCIe and SATA connectors power up your GPU and storage disks respectively. By the end, you’ll also get some insights on a Molex connector, which is, however, quite less used these days.
Table of Contents
24 Pin ATX Power Connector
It is the largest connector on a PSU that supplies power to the main board, including RAM, chipsets, and onboard storage devices (like a NVMe SSD.)
If you observe these connectors closely, you will find that it has 24 pins arranged in 2 rows, 12 on each.
For instance, you can see the ATX power connector that came with my CORSAIR RM850X PSU. It can be easily plugged into the motherboard that has a 24-pin ATX header.
However, you may also find some connectors that are divided into two blocks of 20 pins and 4 pins. The (20+4) pin setup was introduced for enhanced compatibility, allowing you to use the same connector regardless of the pin setup on your main board.
For instance, if you have an older motherboard with a 20-pin ATX header, you can simply attach the 20 pins block and let go of the four pins block.
Coming to the PSU side, you will see a “24PIN ATX” label to connect the ATX power connector. However, the ATX port on the PSU may not always have a 24-pin setup.
For instance, my CORSAIR RM850X PSU has a 28-pin configuration, in a set of (18+10.) The additional 4 pins are integrated to sense voltage drop in the component end, if any, and report it back to the PSU.
Now that you know the basics of an ATX power connector, let me show you how to connect it to your main board.
The ATX header is generally found in the rightmost part of a motherboard, usually with an ATX or ATX_PWR1 label. Below is my ATX header on a GIGABYTE TRX40 AORUS MASTER.
You can simply locate it on your board and plug in the connector. For simplifying the connection process, the connectors are notched and keyed one side, making it almost impossible to insert the cable incorrectly.
12V CPU Power Connector
As you might have guessed, the CPU power connector is the one that powers your CPU.
Referring back to the ATX power connector, it does supply some power to the CPU. However, not enough that it can operate correctly. Your system can not boot without the 12V CPU power connector installed.
Therefore, PSU manufacturers provide a dedicated power connector to ensure proper voltage supply and stability to the CPU.
Coming to the pin configuration, the CPU power connector either has a 4-pin, 8-pin, (8+4) pin, or an (8+8) pin setup. Among all, the 8-pin setup is widely used these days and considered a standard. The 8-pin setup is detachable into two blocks of (4+4) as you can see in my CORSAIR RM850X PSU connectors.
While the 8-pin configuration is backward compatible with the 4-pin ones, the 4-pin ones are not. To be more precise, you can plug the 8-pin connector to the 4-pin header on your motherboard, leaving one-half disconnected but not vice-versa.
However, no matter the setup, you can simply connect it to the ATX_12V header that lies near the CPU socket on your motherboard.
Some high-end boards may even include two ATX_12V headers, like in my GIGABYTE TRX40 AORUS MASTER. Generally, the second one is provided to accommodate a 4-pin or 8-pin auxiliary connector that provides extra power and stabilizes the overclocked CPU. As such, you need to grab two CPU power connectors and plug them into each header.
Coming to the PSU side, you will find a dedicated port with 8 pins to plug the CPU connector. They are generally labeled as “CPU” to help you connect effortlessly.
The next connector in our list is the PCIe connector which is generally used to power up the GPUs.
In general, if you have a low-end GPU rated below 75W, the power delivered from the PCIe x16 slot is sufficient to operate it. To be more precise, you don’t need to connect your GPU to PSU in such cases. However, if you have a power-hungry GPU, it does require a connection with the PSU.
You often get multiple PCIe connectors with your PSU in a daisy chain fashion making it easier to connect more than one PCIe component.
Similar to the standard 12V CPU power connector, the PCIe connector also has an 8-pin configuration. However, unlike the CPU ones, these are divided into two detachable blocks of 6-pin and 2-pins respectively. There are also other variants like one with the 12 or 16 pins.
While the (6+2) pins PCIe connector is sufficient to supply power to the mid-range GPUs, you will require 12 pins or 16 pins to feed the power-hungry GPUs. For instance, you will find two 8-pin ports (16 in total) on a GeForce GTX 1080 Ti GPU.
Similarly, if you have a high-end GPU that requires a single 16-pin connector, you should opt for PCIe 5 compatible ATX 3.0 PSUs like MSI MPG A1000G PCIE 5 & ATX 3.0 Gaming Power Supply. Such PSUs have a dedicated 16-pin port (+12VHPWR) to accommodate those connectors and provide up to a whopping 600W.
Additionally, the high-end GPUs are bulkier in size, making it difficult to plug the PCIe connector into it, often when you are using a smaller PC case. In such cases, you can use a PCIe 90 Degree Adapter to get the job done.
Coming to the PSU side, they have the same 8-pin configuration that resembles the CPU ones.
While you can see separate 8-pin ports for CPU and PCIe (VGA) in some PSUs like in my EVGA Supernova 550 G3, some of them may have the same port for both of them.
So, make sure you inspect the label and insert the connectors accordingly. If the labels are not clear, you may refer to the manual of your PSU to identify the respective ports.
As the name suggests, this connector is used to power SATA interface devices on your system. It can either be storage media like a hard disk drive and Solid State Drive (SSD,) or other supplementary components like a RGB and fan controller device.
Talking about the pin configuration, it has a single block of 15 pins enclosed in a flat L-shaped housing. The unique shape of the connector helps you connect it to a SATA interface device effortlessly. Below you can see the SATA connector that came with my CORSAIR RM850X PSU.
Coming to the PSU side, the connector has a set of 6 pins and a corresponding port labeled “PERIF” or “PERIPHERAL & SATA” to connect to. If you are having any problems with the connector, you can also refer to our comprehensive guide on how to connect the SATA power cable.
The newer standards like PCIe and SATA have almost replaced the use of Molex connectors these days. However, if you got one, you can use it to power the Molex interface devices like a CD/DVD drive, floppy disk drive, or a PATA interface hard drive.
Additionally, you can also pair Molex connectors with the SATA adapters. It can be helpful to power multiple SATA disks if the existing connectors are insufficient.
These connectors generally have a 4-pin configuration in a single row. But you might also find ones that have 4 pins, two on each row. Some of them even have a Berg connector at the end to power a few variants of floppy drives.
Coming to the PSU side, these connectors are pretty similar to the SATAs and have a set of 6 pins.
While some PSUs provide a dedicated “PERIF” port for Molex connectors like in my EVGA Supernova 550 G3, some may have the same port for SATA and PERIF like in CORSAIR RM850X PSU.
You should always read the label on your modular or semi-modular PSU and insert the connector accordingly. However, you don’t need to worry much if you have a non-modular PSU.
Further, I also recommend you only use the proprietary connectors (that came bundled with your PSU.)
For instance, you can see above how the pin configuration of a Molex connector differs between my CORSAIR RM850X and EVGA Supernova. The difference in pinouts may even end up damaging your device if you swap the cables.