Extended memory interface

Systems, apparatuses, and methods related to extended memory communication subsystems for performing extended memory operations are described. An example apparatus can include a plurality of computing devices coupled to one another. Each of the plurality of computing devices can include a processing unit configured to perform an operation on a block of data in response to receipt of the block of data. Each of the plurality of computing devices can further include a memory array configured as a cache for the processing unit. The example apparatus can further include a first plurality of communication subsystems coupled to the plurality of computing devices and to a second plurality of communication subsystems. The first and second plurality of communication subsystems are configured to request and/or transfer the block of data.