The energy consumption of memory is one of the important metrics to evaluate memory systems. However, previous approaches such as using cycle accurate CPU and memory simulators require a long execution time for simulation. We are developing a model of energy consumption of DRAM- and NVM-based main memory, which allows estimating the energy consumption of a memory subsystem from easily observable performance metrics in real computer systems. In this paper, we conducted preliminary experiments using various types of workloads and observed the correlation of the memory throughput and energy consumption of DRAM. We used hardware performance counters to obtain memory throughput and energy consumption with minimum performance overhead.