ATX Version 3.0 Multi Rail Desktop Platform Power Supply

Design Guide

ID 336521
Date 01/02/2022
Version 2.0
Document Table of Contents


In general, more venting in a power supply case yields reduced airflow impedance and improved cooling performance. Intake and exhaust vents should be large, open, and unobstructed as possible so as not to impede airflow or generate excessive acoustic noise. In particular, avoid placing objects within 0.5 inches of the intake or exhaust of the fan itself. A flush-mount wire fan grill can be used instead of a stamped metal vent for improved airflow and reduced acoustic noise.

The limitations to the venting guidelines above are:

  • Openings must be sufficiently designed to meet the safety requirements described in Chapter Chapter 9.
  • Larger openings yield decreased EMI-shielding performance. Refer to Chapter Chapter 8.
  • Venting in inappropriate locations can detrimentally allow airflow to bypass those areas where it is needed.