Embodiments of the present disclosure provide a method, an apparatus, an additional power supply, and a mainboard system for supplying power to a processor. The method comprises determining whether an additional power supply is able to provide extra power required by a processor in response to receiving a first signal from a power supply unit that supplies power to the processor. The first signal indicates that the power required by the processor exceeds maximum power that can be provided by the power supply unit. The method further comprises supplying power to the processor by at least the additional power supply in response to determining that the additional power supply is able to provide extra power. The embodiments of the present disclosure can supply the required extra power to the processor from the additional power supply so as to optimize the performance of the processor in an acceleration mode.