List of computer PSU form factors ATX PS/2 This is by far the most popular PSU form factor and is often called the “standard ATX PSU” Standard dimension for this form factor is: 150mm (W) x 86mm (H) x 140mm (D) PSU with depth longer than 140mm can still be considered as an ATX PS/2 model ATX PS/3 This form factor is compatible with ATX PS/2, the only difference is the shorter depth. Many have also called this the “Micro ATX” PSU form factor, which is incorrect as no such standard exists for power supplies. Standard dimension for this form factor is: 150mm (W) x 86mm (H) x 100mm (D) The depth for this form factor may vary from 100mm up to 139mm SFX This form factor is popular with small computer cases and is also often wrongly referred to as “Micro ATX” power supplies.  Because this standard is smaller than ATX PS/2 in all dimensions, it can be used in cases that support ATX PS/2 with simple adapters or brackets. Some retail SFX power supplies are sold with adapters included. Standard dimension for this form factor is: 125mm (W) x 51.5mm (H) x 100mm (D) There are variations for this form factor that have longer depth. Flex ATX This form factor is often used in small computer cases and is sometimes wrongly referred to as “Mini-ITX” PSU. Standard dimension for this form factor is: 81.5mm (W) x 40.5mm (H) x 150mm (D) There are variations for this form factor that have longer depth TFX This form factor is commonly…