Power Connectors and Cables

In the last post, I mentioned that the output of a PSU comprises of multiple types of power cables that are used to power up various components of a CPU. Each type of cable is designed to work perfectly with different devices. Each type of cable has its corresponding type of connector at the end. The latest revision, PCI Express 2.0 for the specifications of various connectors adds the support of 12V power rails along with 3.3V and 5V power rails.
The types of connectors are:
  • ATX 24 (20+4) pin main power cable: The 20 pins of this connector are to provide power to the motherboard including the IC's on it. It also connects to the on/off switch on the CPU with which we turn-on the computer. The additional 4 pins are to power the PCI and PCI-E expansion slots of the motherboard.




  • 4 pin / 8 pin (12V) main cable: This cable supplies power to the processor. The 8 pin cable is used in case of multiple processors.



  • 6 pin / 8 pin (12V) PCI-E power cable: Either the 6-pin or the 8-pin or two cables of either of them are used to power higher-grade GPU (graphics card) installed additionally on the PCI-E slot of the motherboard.


  • SATA power cable: This sleek power connector powers SATA drives including hard disk drives(HDD) and optical drives.


  • 4 pin Floppy drive cable: Used to power Floppy Disk Drives (FDD), it may go out of fashion along with the declining usage of floppy disks.
  • 4 pin peripheral (Molex) connector: This is the oldest original power connector that is still in use widely. It can be used to provide power to HDD's, optical drives, cooling fans, FDD's, case lights. Converters are available to convert its connector to other types of connectors but, it is strictly NOT recommended.

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