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PSU Form Factor [Explained]

PSU form factor defines the dimension, mounting hole positions, and connector layouts of a PSU.

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A PSU comes in different form factors that ensure compatibility and physical fitness within your build. Choosing the correct PSU form factor is crucial for better airflow and proper installation.


Key Takeaways

  • The PSU form factor is the physical dimensions and the layout of a power supply.
  • There are many form factors, but ATX, SFX, and TFX are the popular ones.
  • All these form factors have different dimensions and wattage capacities since they are made for different PC cases.

What Are PSU Form Factors?

PSU form factor defines the physical dimension[1], mounting hole positions, and connector layouts of a power supply. The most common form factors are as follows:

ATX (Advanced Technology Extended)

Power Output Specifications (Image By Tech4Gamers)
MSI MPG A850G ATX (Image By Tech4Gamers)

The most widely used form factor is ATX[1]. ATX is suitable for the majority of PCs and provides excellent space for components, cooling technologies, and cable management. There are two sub-types of ATX:

  • ATX PS/2 (Standard)
  • ATX PS/3 (Slightly shorter)

SFX (Small Form Factor Extended)

Corsair SF1000L Spec Side
Corsair SF1000L SFX (Image by Tech4Gamers)

SFX is designed for small form factor builds or Mini-ITX cases[2]. It is significantly smaller than the ATX and provides ample power for the smaller builds. Also, there are two sub-types of SFX:

  • SFX (Standard)
  • SFX-L (Slightly longer)

TFX (Thin Form Factor Extended)

TFX is primarily used in AIO PCS. Its power output is limited compared to the other form factors, but it has a low-fi design that fits in confined spaces[3].

Comparison Table of PSU Form Factors

Form FactorDimensions (W x D x H)Wattage Capacity
ATX150mm x 86mm x 140mm300W - 1600W+
SFX125mm x 63.5mm x 100mm 300W - 750W
TFX85mm x 65mm x 175mm200W - 400W

Helpful Resources by Tech4Gamers:

References:

  1. Unlock Your Creativity with “Escape Sequence”  | Lenovo US. (n.d.). https://www.lenovo.com/us/en/glossary/form-factor/
  2. Gaming, C. (2024, May 1). Difference between SFX and SFX-L PSUs. https://www.corsair.com/us/en/explorer/diy-builder/power-supply-units/whats-the-difference-between-sfx-and-sfx-l-power-supplies/
  3. ATX OR SFX: WHICH PSU IS RIGHT FOR YOU? | Cooler Master. (n.d.). https://www.coolermaster.com/en-global/guide-and-resources/atx-or-sfx/

Frequently Asked Questions

What is the form factor in a power supply?

The Form factor of a power supply defines its dimensions, connector type, and overall design.

What is the difference between SFX and ATX?

SFX units are smaller and designed for compact build, while ATX units are larger and fit standard desktop PCs.

Can I use SFX PSU in ATX?

Yes, you can use an SFX PSU in an ATX case with an SFX-to-ATX adapter.

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