A method of requesting data items from storage. The method comprising allocating each of a plurality of memory controllers a unique identifier and assigning memory transaction requests for accessing data items to a memory controller according to the unique identifiers. The data items are spatially local to one another in storage. The data items are requested from the storage via the memory controllers according to the memory transaction requests and then buffered if the data items are received out of order relative to an order in which the data items are requested.