A flash memory, a memory module, a computer-readable recording medium and an operating method are provided, which can perform a flexible setup by a flexible clock scheme. A NAND-type flash memory 100 of the invention includes: a memory array 110 having NAND-type memory cells, a controller 150 including a processor and a ROM/RAM, and a system clock generating circuit 200 configured to generate an internal system clock signal. The ROM/RAM is at least stored with setup commands for a setup of the flash memory, and the processor processes the setup commands based on the internal system clock signal during a setup period. The controller 150 further controls the system clock generating circuit 200, so that a frequency of the internal system clock signal becomes high speed during the setup period.