Abstract: This invention involves the efficient placement of a pair of main boards within a given computer chassis. The available density of CPUs and main boards that may be provided for a given chassis height is advantageously increased through the use of a dual opposing main board configuration. With this configuration, two main boards are mounted opposing each other within a chassis. They are placed such that their I/O connectors are on the same side of the main board to improve usability. They are also mounted within the chassis so the components on the main boards (such as the cards, CPU fans, CPU heat sinks, etc.) do not physically interfere with each other. This configuration improves CPU density and cooling, especially when stacked with like chassis.