NAND Flash endurance can also be quantified in terms of the terabytes written (TBW) along with P/E cycles. The TBW of NAND Flash media, in simple terms, is influenced by the total capacity of the media, the endurance rating in P/E cycles and the Write Amplification Index/Factor. Write Amplification Index or Factor is the ratio of total bytes of data written to the NAND Flash media to the total bytes written by the host system.