A method for performing a write operation in a random access memory (RAM) includes selecting a target block in a RAM with a greatest number of invalid pages, reading valid pages from target block, when a number of invalid pages is greater than a predetermined threshold, performing a bitline-wise block erase of the target block in said RAM, and copying-back valid data to the erased target block in a row-by-row set operation, wherein the erased target block is written with the valid data. Performing the bitline-wise block erase includes sequentially powering on each bitline with a predetermined reset voltage where all other bitlines and wordlines are grounded.