Controlling air recirculation in multi-processor systems

Abstract

With the increased popularity of multi-processor systems and ever-increasing power requirements, the problem of preventing re-circulation of preheated air is becoming more important to consider in system-level designs. For the common setup of a desktop tower chassis with two impingement-cooled heat sinks and one or more system fans, the problem is that pre-heated air exiting the heat sink from the upstream processor can cause a significant rise in the intake temperature for the other processor. For many systems, temperature rises of up to 10 degrees were observed for the rear processor over the front one, all other factors being equal. Air deflectors were designed with the goal of controlling this problem in multiprocessor systems. They have been optimized and tested through experiments. The effect of these devices was that the temperature of the downstream processor dropped by 68 degrees in most cases, and there is usually a smaller effect on the temperature of the upstream processor. Consequently, higher speed processors could be supported without major changes to chassis, system layout, or heat sink cost. This method could be applicable not only to computer processors, but to general convection-cooled systems with multiple heat sources.