An integrated circuit device comprises a semiconductor substrate, a first memory block on the substrate comprising NAND memory cells, a second memory block on the substrate comprising NAND memory cells, and controller circuitry. The first and second memory blocks are configurable to store data for a first pattern of data usage in response to a first operation algorithm to read, program and erase data, and for a second pattern of data usage in response to a second operation algorithm to read, program and erase data, respectively. The controller circuitry is coupled to the first and second memory blocks, and is configured to execute the first and second operation algorithms, wherein a word line pass voltage for read operations applied in the first operation algorithm is at a lower voltage level than a second word line pass voltage for read operations applied in the second operation algorithm.