A power control system includes a first power supply, a processor, a second power supply that outputs a part of a power outputted from the first power supply to the processor, a memory, a memory controller that control the memory, a third power supply that outputs the part of a power outputted from the first power supply to the memory, and a controller that includes a first control circuit and a second control circuit, the first control circuit instructs the processor to lower an operating frequency, instructs the second power supply to lower an output voltage, and instructs the memory controller to lower a frequency of access to the memory, and the second control circuit instructs the processor to raise an operating frequency, instructs the first power supply to raise a voltage, and instructs the memory controller to raise a frequency of access to the memory.