Crucial has started shipments of its fastest and highest density server-class memory modules to date. Crucial’s 128 GB DDR4-2666 LRDIMMs are compatible with the latest memory-dense servers. These modules should be usable in both AMD EPYC systems and Intel Xeon systems, however Crucial states that they are optimized for Intel’s Xeon Scalable CPUs (Skylake-SP) launched earlier this year, and are aimed at mission-critical RAM-dependent applications. Due to the complexity of such LRDIMMs, and because of their positioning as super dense memory, the price is very high.

Crucial’s 128 GB LRDIMMs are rated to operate at a 2666 MT/s interface speed with CL22 timings at 1.2 V. The module is based on Micron’s 8 Gb DRAM ICs, are made using 20 nm process technology, and are assembled into 4Hi stacks using TSVs. The LRDIMM uses 36 of such stacks of ICs. Stacking naturally makes organization of the module very complex: we are dealing with an octal ranked LRDIMM featuring two physical ranks and four logical ranks. Making such a module run at 2666 MT/s is a challenge, so they end up running at relatively high latencies (which are higher than CL17 – CL20 specified by JEDEC for DDR4-2666). This can somewhat diminish the benefits of relatively high clocks, but is not surprising in order to keep them stable.

The key advantage of 128 GB LRDIMMs is their density. For example, a dual-socket Xeon Scalable platform using the -M suffixed processors, featuring 12 memory slots, can expand the maximum memory size by 2X to 1.5 TB from 768 GB by using 128 GB LRDIMMs over 64 GB LRDIMMs. For DRAM-dependent applications, such as large databases, holding everything in memory is the most important thing for performance. Obviously, such performance advantage will come at a price.

Specifications of Crucial's Server 128 GB DDR4-2666 LRDIMM
  Module Capacity Latencies Voltage Organization
CT128G4ZFE426S 128 GB CL22 1.2 V Octal Ranked

According to Crucial, production of 128 GB LRDIMMs involves 34 discrete stages with over 100 tests and verifications, making them particularly expensive to manufacture. These costs are then passed to customers buying such modules. The company sells a single 128 GB DDR4-2666 module online for $3,999 per unit, but server makers naturally get them at different rates based on quantity and support. At this rate, a full Xeon-SP system would cost $48k per socket, or for an EPYC system at 2 TB for each CPU, it would come to $64k per socket. At these rates, spending $13k or $4k for a CPU suddenly becomes a diminished part of the initial hardware cost (which is some justification for high-priced CPUs). At the Xeon-SP launch, Intel stated that fewer than 5% of its customers would use high memory capacity server configurations, though given how big the server market is, that is still a sizeable portion.

Crucial says that its 128 GB LRDIMMs are compatible with Xeon Scalable-based servers from various OEMs as well as software like Microsoft SQL and SAP HANA. We would expect them to be compatible with AMD EPYC servers too, however Crucial drives home the point about being optimized for Intel. Each module is tested individually to ensure maximum reliability for mission-critical applications. Specific support for these modules will be down to OEMs, as with other memory.

Related Reading

Source: Crucial

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  • Xajel - Sunday, December 03, 2017 - link

    Good analysis indeed, thought looking at the target market, the verification, quality, testing & binning will take a big chunk of the margin, so the actual margin is lower also.. not to say the margins are low as server market is one of the biggest margins out there, but these tests are more serious than even the regular server grade modules. Reply
  • ddrіver - Sunday, December 03, 2017 - link

    The R&D that goes into making this kind of product will definitely increase the price. And because it's a niche the only way to justify the investment is if you increase the price.

    But think about it: a 64GB one costs ~$900 on regular distribution channels. The 128GB probably costs triple to manufacture (given the arguments above) so I expect it to cost in the $5000 zone.

    And I also expect someone to say they can buy 8 faster 16GB sticks so why would anyone buy this one. Plus no OC. Plus no RGB lighting. Not even a cool heatspreader. Because this is what AT community became recently.
    Reply
  • PreacherEddie - Sunday, December 03, 2017 - link

    I can buy a gross of pencils, a case of paper, and two sharpeners (back ups are important) for less then $50. In 8,000 years, I will have saved nearly $4000. Reply
  • lmcd - Sunday, December 03, 2017 - link

    So this is how the NRA justifies requiring all gun registration in certain states be via paper records? Damn thanks sir, you've provided me with enlightenment. Reply
  • Lord of the Bored - Sunday, December 03, 2017 - link

    $13.37, actually. Reply
  • ddrіver - Sunday, December 03, 2017 - link

    Ah, was waiting for you. I mean you can't stay away from things you can't understand (https://www.anandtech.com/comments/12105/cherry-la... Reply
  • lmcd - Sunday, December 03, 2017 - link

    I heard they stored the coordinates to your future residency in hell on an Optane hard drive. Reply
  • lmcd - Sunday, December 03, 2017 - link

    Naturally, the goal was to get you there quicker. Reply
  • menting - Sunday, December 03, 2017 - link

    spend 20 seconds on DRAMeXchange to look at spot prices instead of typing up what you posted and you might learn something. Reply
  • RaistlinZ - Saturday, December 02, 2017 - link

    What...no RGB? Reply

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