In a data processing system, at least one processing node is configured to perform computations for a multi-stage process whilst at least one other processor performs the load/unload operations required to calculate a subsequent stage of the multi stage process. An exchange of data then occurs between the processing nodes. At a later time, at least one processing node performs calculations using the data loaded from storage, whilst at least one other processor performs the load/unload operations required to calculate a subsequent stage of the multi stage process.