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The PC Power Supply Guide for the Masses

  1. Introduction
  2. PSU Abbreviations and Glossary
  3. Connectors used in a PC Power Supply
  4. PSU cables: Non-Modular, Modular and the middle-ground!
  5. Power Supply Labels
  6. Power Supply Form-Factor- ATX12V
  7. Power Supply Form-Factor- SFX12V
  8. Basic requirements of a power supply
  9. Facts about 80 Plus Certification
  10. Protection Circuits and Features
  11. List of Power Supplies, OEM and Review Links
  12. Common PC Power Supply Myths
  13. Resource Links and References
  14. View All

Intel designed SFX (Small form factor) power supply for smaller sized Micro-ATX setups, though in the DIY scene, most Micro-ATX cases that I am familiar with at the time of writing use standard ATX form factor power supply.

Unlike other form factors, this has 5 design variants. The changes and the implementation of the connectors were the same as ATX design, but then there was a newer form factor within the SFX category to provide space for certain components.

Since these variants are present for certain form-factor micro-ATX case design, the mounting hole dimensions are also different. Because of physical restriction, SFX form factors will provide limited power output and hence restrict certain upgradability, depending on the quality of the power supply’s DC output.

The difference between ATX and SFX is only physical. The choice of multiple SFX variants and ATX sized power supply ultimately depends on the case. Usually, such cases come with pre-mounted SFX power supply. Few manufacturers make their own giving a better choice for consumers. Silverstone is the one company that I can find providing SFX power supplies. They also have three SFX power supplies with modular cabling.


A typical SFX power supply has a 60mm fan mounted towards the wire harness area when passive vents at the AC Plug area. The height of the standard SFX is 63.5mm.


Another variant is similar to the standard SFX, but with a slimmer design accommodating a 40mm fan. This allowed the height of the power supply to be a 50mm.

There are two variants in this design. The first one has a longer width of 125mm, but the depth reduced down to 100mm. The second one has a shorter 100mm width, but a 125mm depth.


  1. Koolest ripper guide to What is and what is not on SMPS!
    Thanks for adding those SMPS suggestions! 🙂

  2. Much appreciated!

    I plan on putting more guides per component so that many people from newbies to regular users can understand “what is” and “what is not” for many components to help them make better purchase decisions! This way, we can guide even the newest of end users to understand whenever they read our reviews!

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