Author: Ryan Smith AnandTech
Back in March, Samsung first demonstrated their next-generation 64GB DDR4 Registered DIMMs. Based on Samsung’s new 16Gbit DDR4 memory chips, these new RDIMMs would offer 64GB of memory capacity in a standard dual-rank RDIMM, effectively doubling the capacity of mainstream servers. Now this afternoon, in conjunction with AMD and HPE, Samsung is announcing that they’ve kicked off mass production of these DIMMs.
Up until now, the largest dual-rank RDIMM available has been 32GB, owing to the capacity limitations imposed by 8Gbit memory chips. 64GB RDIMMs have been available, but these require a more esoteric quad-ranked configuration that comes at a higher cost and with additional performance and compatibility tradeoffs. However now that the company is finally producing 16Gb DDR4 chips, Samsung can produce simpler “monolithic” dual-ranked DIMMs of the same capacity, culminating in these new DDR4-2666 RDIMMs.
Marking the release of these DIMMs, Samsung has been working with AMD and HPE to validate the new DIMMs and demonstrate the benefits of them. The first system that’s getting qualified to use the new RDIMMs is HPE’s ProLiant DL385 Gen10, a sizable dual-CPU AMD EPYC 7000-based system with 16 DIMM channels. With dual-ranked RDIMMs it’s possible to install them at two DIMMs per channel, meaning the total capacity of the system is 32 DIMMs, or 2TB in a single EPYC server. Meanwhile HPE’s ProLiant DL325 Gen10 – their single-processor counterpart – is also being qualified, ultimately allowing it to reach 1TB of RAM.
In terms of performance, Samsung is stating that power consumption is 19% lower than a 2x32GB RDIMM setup, similar to their claims from earlier this year. At HPE’s Discover event next week, the company will also be showing off the RDIMMs and talking about performance – I’m hearing that they’re claiming a 12% performance improvement, though it’s not clear whether the performance improvement is from higher memory speeds and tighter latencies from denser DIMMs, or if Samsung is using another metric.
Ultimately however, 64GB RDIMMs are the tip of the iceberg. Once applied to quad and octal-ranked DIMMs with TSV, Samsung will be able to churn out 256GB DIMMs. Samsung expects to be sampling these DIMMs by the end of the year.