Disclosed is an apparatus including a datapath and a test circuit. The datapath is configured to transfer data between a memory core and an IO interface. The datapath includes a plurality of circuits, and a memory core interface. The plurality of circuits operates according to a supply voltage. The test circuit is coupled to the datapath, and configured to determine, from a set of operable voltage levels of the supply voltage, a first minimum operable voltage level for the datapath to operate for the data traversing the datapath at a first frequency.