Modern memory systems are equipped with multiple channels to achieve a higher memory bandwidth. Since the multi-channel memory system focuses on achieving a high memory bandwidth, data are allocated to all the channels. Hence, when the memory system is accessed, all the channels are activated until the next DRAM refresh starts. Therefore, when executing compute-intensive applications that do not need a full memory bandwidth, the memory modules just waste power because of an unnecessary activation. To overcome this problem, this paper proposes a data allocation method, which controls the number of accessed channels for reducing energy consumption according to applications' demands for the memory bandwidth. The evaluation results show that the proposed method reduces the energy consumption by up to 10.4%, and 5.3% on average without degrading the performances.