1. A node comprising: at least one memory control unit configured to couple to an industry standard memory interface for coupling to a memory that comprises one or more memory modules designed to communicate on the industry standard memory interface to the memory control unit; and at least one coherence unit configured to transmit and receive coherence messages to and from other nodes to maintain coherent memory among the nodes, the coherence messages conveyed on a second interface to which the coherence unit is coupled, wherein the second interface includes at least a physical layer as specified by the industry standard memory interface.