A common motherboard interface accommodates processor modules of different processor architectures. The system comprises an interface for communicating with a processor module inserted at the motherboard. The interface receives an identifier signal from the processor module. The identifier signal identifies the processor module architecture. An architecture selection circuit selectively exchanges processor architecture specific signals with the processor module based on the identifier signal. In this manner, a multiple of processor modules of completely different processor architectures can share a common motherboard, thereby providing a system that can be field-upgraded by processor modules of different architectures, or simply allowing the same motherboard to be employed in two different products of different processor architectures.