A storage device includes a memory unit, an access monitor, and a memory configurator. The memory unit includes a plurality of memory blocks. The access monitor is configured to monitor whether an access mode of the memory unit is a continuous-access mode or a random-access mode, to generate a monitor signal. The memory configurator configures, according to the monitor signal, any of the memory blocks to be either in a cache mode or a SRAM state to generate a configuration signal.