The following is a list of guidelines to be used when integrating a system. Specific mention of Baby AT, ATX, or microATX components is made where necessary.
Provide sufficient air vents: Systems must have adequate air vents in addition to a fan. Chassis vents must be fully functional. Integrators should be careful not to select chassis that contain cosmetic vents only. Proper location of vents results in a good stream of air flowing over the processor. For Baby AT systems, intake vents on the front of the chassis allow air to flow over the processor. For ATX and microATX systems, exhaust vents in the chassis allow air already forced over the processor (by the power supply) to flow out of the chassis.
Power supply air flow direction: It is important to choose a power supply with a fan that moves air in the proper direction. For Baby AT systems, the power supply fan acts as an exhaust fan, venting system air outside the chassis.
Power supply fan strength: For some chassis that are running too warm, changing to a power supply with a stronger fan can greatly improve airflow. If that is not an option, add an additional system fan.
System fan--should it be used? Some chassis may contain a system fan to assist airflow. A system fan is typically used with passive heatsinks. With fan heatsinks, however, a system fan can have mixed results. Thermal testing both with a system fan and without the fan will reveal which configuration is best for a specific chassis. When a fan heatsink is used on the processor, changing to a power supply with a stronger fan is usually a better choice than adding a system fan.
System fan airflow direction: When using a system fan, ensure that it moves air in the same direction as the overall system airflow. For example, a system fan in a Baby AT system should act as an intake fan, pulling in additional air from the front chassis vents.
Protect Against Hot Spots: A system may have a strong airflow, but still contain "hot spots." Hot spots are areas within the chassis that are significantly warmer than the rest of the chassis air. Such areas can be created by improper positioning of the exhaust fan, adapter cards, cables, or chassis brackets and subassemblies blocking the airflow within the system. To avoid hot spots, place exhaust fans as needed, reposition full-length adapter cards or use half-length cards, reroute and tie cables, and ensure space is provided around and over the processor.
