Understanding and mitigating refresh overheads in high-density DDR4 DRAM systems
Janani Mukundan, Hillery C. Hunter, Kyu Hyun Kim, Jeffrey Stuecheli, José F. Martínez · 2013
Recent DRAM specifications exhibit increasing refresh latencies. A refresh command blocks a full rank, decreasing available parallelism in the memory subsystem significantly, thus decreasing performance. Fine Granularity Refresh (FGR) is a feature recently announced as part of JEDEC's DDR4 DRAM specification that attempts to tackle this problem by creating a range of refresh options that provide a trade-off between refresh latency and frequency.