A data storage system that provides improved reliability and performance comprises a first memory device including a plurality of first storage components and a first memory controller, the first memory controller controls operation of the first storage components, a second memory device including a plurality of second storage components and a second memory controller, the second memory controller controls operation of the second storage components, a grading device determining grades for each of the first storage components and the second storage components, and a system controller that the location of data based on the grades of the first storage components and the second storage components.