1. A graphic data processing apparatus, comprising: a CPU having at least two cores; a GPU configured to process graphic data; a usage level checking unit configured to check a usage level of the CPU and a usage level of the GPU; a control unit configured to compare the checked usage level of the CPU with a usage level reference of the CPU and to compare the checked usage level of the GPU with a usage level reference of the GPU, and to control one core of the CPU to process system data and another core of the CPU to be assigned to the GPU for processing the graphic data in accordance with the checked usage levels of the GPU and the CPU provided by the usage level checking unit, wherein the control unit allows processing of the graphic data only by the GPU if the control unit determines that the checked usage level of the GPU is not larger than the usage level reference of the GPU and/or the checked usage level of the CPU is not smaller than the usage level reference of the CPU, and wherein the control unit allows processing of the graphic data in parallel by the GPU and the assigned core of the CPU if the control units determines that the checked usage level of the GPU is larger than the usage level reference of the GPU and, at the same time, the checked usage level of the CPU is smaller than the usage level reference of the CPU; a data dividing unit configured to receive the graphic data from the control unit and to divide the received graphic data when the control unit allows processing of the graphic data in parallel by the GPU and the assigned core of the CPU; a data combining unit configured to combine, after the GPU and the assigned core of the CPU have respectively processed the divided graphic data by the data dividing unit, the processed graphic data to display the combined graphic data on a display unit; and a user selection unit configured to allow a user to manually select whether to process the graphic data only by the GPU or in parallel by the GPU and the assigned core of the CPU, wherein the manual selection of the user made through the user selection unit is overridden by the control unit based on current battery information associated with the apparatus.