An energy- and performance-aware DRAM cache architecture for hybrid DRAM/PCM main memory systems

The last few years have witnessed the emergence of a promising new memory technology. Phase-Change Memory (PCM) is increasingly viewed as an attractive alternative for the memory sub-system of future microprocessor architectures, mainly because of its inherent ability to scale deeply into the nanoscale regime, and its low power consumption. However, PCM´s write performance is its Achilles´ heel, especially when compared to the prevalent DRAM technology. This weakness necessitates the deployment of hybridized solutions that fuse DRAM and PCM, in order to attain high overall system performance. In this paper, we set out to explore how various DRAM/PCM hybrid configurations affect system performance and energy consumption, and then proceed with the presentation of a novel architecture that maximizes performance without adversely affecting power efficiency. An energy-delay product improvement of 42.2%, on average, over conventional hybrid structures, is demonstrated.