First, this paper introduces the background of PCM. This paper surveys architectural research work to optimize PCM memory systems.

However, PCM technology has the following three drawbacks: long write latency, limited write endurance, and high write energy, which raises challenges to its adoption in practice. PCM memory systems have become a hot topic of academic and industrial research. Compared to DRAM, PCM (phase change memory) has better scalability, lower energy leakage, and non-volatility. It is difficult for DRAM (dynamic random access memory) based memory system to satisfy the memory capacity requirement due to its limited scalability and high energy consumption.

As the scaling of applications increases, the demand of main memory capacity increases in order to serve large working set.