The volatile DRAM faces several challenges, such as low scalability and high energy consumption. It's difficult for DRAM to satisfy the increasing capacity and energy requirement of applications. Emerging Non-Volatile Memory (NVM) is a promising technology to complement DRAM memory. Such NVMs include PCM, MRAM, RRAM, and the latest 3D XPoint. NVMs show higher scalability, and thus larger capaticy. However, NVMs also suffer from write issues, including long write latency, high write energy, and limited write endurance. Thus, hybrid memory consisting of DRAM and NVM is an ideal solution for memory system. To evaluate the performance and energy efficiencies of hybrid memory, we develop a hybrid memory simulator, called HMSim1.