This paper presents a new partitioning algorithm to perform matrix multiplication on two interconnected heterogeneous processors. Data is partitioned in a way which minimizes the total volume of communication between the processors compared to more general partitionings, resulting in a lower total execution time whenever the power ratio between the processors is greater than 3:1. The algorithm has interesting and important applicability, particularly as the top-level partitioning in a hierarchal algorithm that is to perform matrix multiplication on two interconnected clusters of computers.