There has been quite a lot of interest over the past few days about the apparently-inadvertent disclosure by Intel of its server platform roadmap. Detailed coverage in The Platform showed a couple of slides with key memory information for the upcoming Purley server platform which will support the Xeon “Skylake” processor family. (A review of this post on 7/13/17 revealed that The Platform’s website has disappeared. The above link and the next one no longer work.)
One slide, titled: “Purley: Biggest Platform Advancement Since Nehalem” includes this post’s graphic, which tells of a memory with: “Up to 4x the capacity & lower cost than DRAM, and 500x faster than NAND.”
The Memory Guy puzzled a bit about what this might be. The only memory chip technology today with a cost structure lower than that of DRAM is NAND flash, and there is unlikely to be any technology within the leaked roadmap’s 2015-2017 time span that will change that. MRAM, ReRAM, PCM, FRAM, and other technologies can’t beat DRAM’s cost, and will probably take close to a decade to get to that point.
Since that’s the case, then what is this mystery memory? If we think of memory systems, rather than memory chips we can come up with one very plausible answer. Intel may be very obliquely referring to Diablo’s Memory Channel Storage, or some similar approach.
Diablo’s approach, which places NAND flash on the memory bus, provides a larger amount of memory on a single DIMM than can be done with standard DRAM at a lower cost per gigabyte than DRAM, and its architecture supports higher bandwidth than is available through most NAND flash interfaces.
Although Diablo’s current customers include only SanDisk, with its ULLtraDIMM, and IBM, which sells the SanDisk product rebranded as the eXFlash DIMM, Diablo has repeatedly asserted that it is working with other vendors to increase the adoption of its technology. The Purley slides appear to indicate that Intel has decided to promote the approach.
This would be quite an accomplishment for Diablo, but it fits with a trend that Intel has been supporting for a number of years: to bring flash into the platform in order to unleash the processor’s capabilities.
You can safely bet that I will be watching the Purley platform closely for further disclosures of Intel’s memory plans! As I learn more I will share what I can.