A memory module includes a ground terminal, a power terminal, a voltage regulator down, and a storing unit. The power terminal and the ground terminal are connected to a power source that supplies a first direct voltage. The voltage regulator down is connected to the power terminal and configured for converting the first direct current voltage to a second direct current voltage. The storing unit is connected the voltage regulator down for storing data and reading or writing data when the storing unit receives the second direct current voltage.