We propose memory-aware VM consolidation to achieve energy-efficiency of a data center while enhancing performance of VMs. Consolidation without awareness of the memory-access demand can cause inefficient resource utilization and degrade system performance. In this chapter, we propose efficient consolidation of VMs based on the memory-access demand of these VMs to improve overall system performance. The proposed algorithm, Memory-bus Load Balancing (MLB), is executed by the Global Migration Manger (GMM). We evaluated our algorithm using several simulation setups and several performance metrics, such as performance degradation, VM placement, memory-bus utilization of each server, and energy consumption. The results showed that we could achieve balance in memory-bus utilization of servers and improve performance of the system compared to the CPU-based consolidation approach. Furthermore, we investigated the effectiveness of using the memory DVFS mechanism to achieve efficient energy consumption.