1. A method of memristor cell read margin enhancement, the method comprising: programming a first switched memristor sub-bit of a memristor cell with a first resistive state; and programming a second switched memristor sub-bit of the memristor cell with the first resistive state, the second switched memristor sub-bit being connected in series with the first switched memristor sub-bit, wherein a read margin of the memristor cell is increased relative to a read margin of either of the first switched memristor sub-bit or the second switched memristor sub-bit, and wherein the first and second switched memristor sub-bits of the memristor cell are programmed with the first resistive state to increase the read margin of the memristor cell in a read margin enhancement mode of a cell programmer performing the programming, and the method further comprises: in a normal mode of the cell programmer, storing resistive states of the first and second switched memristor sub-bits independent of one another when storing data in the memristor cell, wherein the read margin enhancement mode and the normal mode are selectable operational modes of the cell programmer.