Identify the connectors of the power supply

October 2017

Power supplies to the PC have the connectors that are vital hardware cables and buses for transferring power to various components in the computer. PC Main is the power connector, also called P1; it connects to the motherboard and powers it. 12 Volts only P10 for system monitoring is responsible for supplying power to the Power Supply Unit's fan. ATX12V 4-pin cable is the second one to connect to the motherboard. The 4-pin connector is for the powering of disk drives. 4 pin power is for the Accelerated Graphics Port graphical cards. Auxiliary cables are additional power supply units. SATA cable connectors are for the hardware devices that SATA plugs into for power. 6-pin connector powers the computer for PCI Express audio-video cards. 6+2 pin for the function of reverse compatibility of the PCI Express card. An IEC 60320 C14 cable uses a C13 cord to connect the PSU to the native power grid.

Here is a quick guide which will help you identify the different types of connectors of your PC's power supply.

Description of the label

The reference on the side, unique to each manufacturer, will allow you to identify the model. For example:

SP = The brand (Spire)
ATX = The standard for the power supply
650WTN = the output (in watts) of the power supply.
PFC = Power Factor Correction (power factor correction, active or passive)


The 20/24 ATX pin

It allows you turn on the motherboard: early models had a 20-pin configuration, whilst the current standard is now 24. Note that it still comes as a block of 20 pins, to which you can add a block of 4 pins. This is to ensure compatibility with older motherboards and their 20-pin connectors.

20/4 connector, divided:

The "ATX P4"

This connector, called P4-ATX (ATX 12V or as), was introduced by Intel for Pentium 4 (hence the name): it plugs into the motherboard and exclusively powers the processor.
Today, most motherboards possess 4 to 8 pins dedicated to powering up the CPU. The latest standards for power supply make use of an 8-pin connector (sometimes called EPS 12V), made up of 2 x 4-pin blocks, again to ensure compatibility with old motherboards and the classic ATX P4.

Connector attached:

The same connector, divided:


The most classic. Still very present in every PC, it is sometimes used directly on the motherboard (MSI) and is used to connect the hard disk and other drives. Some graphics cards may require this connector too.
Note that molex/sata connectors are easily available nowadays.

The SATA connector

Modern power supply must have at least 4 of these, to power up drives at the SATA standard.

The "PCI Express"

Modern graphics cards need more power. They need to power themselves directly from the power block. This is the role of this connector. Originally a 6-pin configuration and now available in 8-pin.
If you plan to buy a powerful graphics card, be careful on this point: your power supply should contain at least two PCI Express slots including one convertible at least 6 / 8 pin as follows:

If your power supply doesn't have an 8-pin connector, there are 6 to 8 adapters:

MOLEX to PCI Express


The use of these adapters is not recommended and requires the power supply to be of good quality and powerful enough to feed the latest graphics card.

The pins

As you can see, all these connectors are fitted with pins. Never force! Take your time, look at the connector and ask yourself two questions: is this correct? is it in the right direction?
Published by jak58. Latest update on March 19, 2012 at 06:28 AM by Virginia Parsons.
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