  We demonstrate approximate storage based on NAND-like spin-orbit torque (SOT)
MRAM, through "device-modeling-architecture" explorations. We experimentally
achieve down to 1E-5 level selectivity. Selectivity and low-power solutions are
established by numerical calculation workflow. System-level power consumption
is evaluated in the 512 KB last-level cache according to 5 quality levels.
Error-tolerant applications, such as image processing, alleviate the demand for
selectivity down to the 5E-2 level, leading to 54% ~ 61% energy-saving. Our
proposal paves the novel and suitable path for high-density and low-power
NAND-like SOT-MRAM.
