A mobile computer with a desktop type processor. The mobile computer further includes a battery, a current sensor, and a clock generator. The battery supplies a current to the desktop type processor. The current sensor is coupled to the battery, and detects a value of the current supplied by the battery. When the value of the current achieves a standard value, the current sensor outputs a change signal. The clock generator is coupled to the current sensor and the desktop type processor respectively, and outputs a clock signal to the desktop type processor based on the change signal from the current sensor so as to change an operational frequency of the desktop type processor and the current supplied by the battery.