Performance and Energy Benefits of MRDIMMs
For server system designers, this work quantifies the performance and energy benefits of upgrading from RDIMMs to MRDIMMs, though it is an incremental evaluation of a known technology.
This paper evaluates a production server with MRDIMMs, showing a 41% bandwidth increase over RDIMMs, yielding 27-41% higher performance for bandwidth-bound workloads and up to 30% energy savings for memory-bound workloads.
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.