Builder’s Guide for AMD Opteron™ Processor-Based
Servers and Workstations
30925 Rev. 3.04 February 2004
30 Hardware Considerations
Chapter 5
• Cables inside the enclosure can cause airflow disruptions. Using cable ties, tie and route the
cables out of the path of the cooling airflow.
• For tower chassis, choose a chassis with power supplies that have both ATX-style bottom air
intake vents and front air intake vents.
• When the system is in a tower chassis, there must be clear space in front of the chassis to allow
cool airflow in and space behind the chassis for the heated air to flow out.
• Rear fans should exhaust air in the same direction—out the back of the chassis.
• Front intake fans may not be of significant benefit to cooling a tower chassis, and should not
be relied upon as the sole fan in a system.
• Testing done by the AMD thermal engineers has shown that the airflow pattern in Figure 21 is
more desirable than the airflow pattern seen in Figure 22 on page 31.
• When the bottom inlet power supply is used, nearly all the air flows near or through the area of
the processor. As a result, the processor remains cooler.
5.1.3 Power Supply Considerations Because heatsinks are heat radiators, like the radiator in an automobile, they need airflow to
function properly. Figure 21 shows desirable airflow through a chassis. Both desirable
configurations use a bottom-inlet power supply.
Figure 21. Desirable Airflow—Power Supply with Bottom Inlet