Performance and Energy Benefits of MRDIMMs

TL;DR

This paper evaluates MRDIMMs, showing they increase bandwidth and performance significantly while enabling energy savings for memory-bound workloads in servers.

Contribution

It provides a detailed performance, power, and energy analysis of MRDIMMs compared to RDIMMs in a production server environment.

Findings

MRDIMMs increase bandwidth by 41%.

Performance for bandwidth-bound workloads improves by 27-41%.

Up to 30% server energy savings for memory-bound workloads.

Abstract

Multiplexed Rank DIMMs (MRDIMMs) have recently emerged as memory devices that enable higher bandwidth without increasing DRAM chip frequencies. This paper presents a detailed performance, power and energy evaluation of a production server with high-end MRDIMM main memory. The memory system upgrade from conventional registered DIMMs (RDIMMs) to MRDIMMs extends the bandwidth by 41% yielding 27-41% higher performance for bandwidth-bound workloads. Additionally, the latency improvement reaches hundreds of nanoseconds, benefiting a broad class of workloads sensitive to memory latency. At the same bandwidth utilization levels, RDIMMs and MRDIMMs exhibit similar power consumption. In the MRDIMM-extended bandwidth region, the performance improvements largely exceed the power increase, delivering up to 30% server energy savings for memory-bound workloads.