Intel Developer Forum – Not Much 3D XPoint Progress

IDF16 FaceAfter a big 3D XPoint launch one year ago almost anyone would expect for Intel to have had a lot of exciting new news to share about the technology at last week’s Intel Developer Forum (IDF).  Those who were watching for that, though, were in for a disappointment.

For readers who don’t remember, Intel and its partner, chipmaker Micron Technology, announced a new memory layer in July 2015 that would enable in-memory databases to expand well beyond the constraints posed by standard DRAM memory. The pair also boasted the additional benefit of being nonvolatile or persistent – data would not be lost if the power failed.  This technology promised to open new horizons in the world of computing.

Intel devoted a lot of effort to promotion and education during the following month’s IDF, and even demonstrated a prototype 3D XPoint SSD that performed seven to eight times as fast as Intel’s highest-performance existing NAND flash SSD – the DC S3700.  Although a DIMM form factor was disclosed, no prototypes were on hand.  Both were given the brand name “Optane”.

Moving forward one year to the 2016 IDF (the source of this post’s odd graphic), The Memory Guy was shown Continue reading

Crossbar or Crosspoint?

Computing Crossbar SwitchThe Memory Guy has recently run across a point of confusion between two very similar terms: Crossbar and Crosspoint.

A crosspoint memory is a memory where a bit cell resides at every intersection of a wordline and a bitline.  It’s the smallest way you can make a memory cell.  Think of the wordlines and bitlines as the wires in a window screen.  If there’s a bit everywhere they cross, then it’s a crosspoint memory.

In most cases a crossbar is a communication path in a computing system.  (Of course, there are exceptions, the main one being a company, Crossbar Inc., that is developing a crosspoint memory technology!) A crossbar communication path is topographically similar to a crosspoint, but its function is to connect a number of memory arrays to a number of processors.  Visualize a vertical column of memory arrays named A, B, C… and a horizontal row of processors named 1, 2, 3… as is illustrated in this post’s graphic.  The crossbar can connect Processor 1 to Memory A, or to any other memory that is not already connected to another processor.  These connections are represented by the circles in the diagram.  You can see that this is an efficient way to allow processors to share a memory space to achieve very high speed inter-processor communications.

Crossbars are quite likely to Continue reading

How Many Kinds of Memory Are There?

Micron's History of Memory TechnologiesWith Micron & Intel’s July 28 introduction of their new 3D XPoint memory both companies touted that his is the first new memory in a long time, and that the list of prior new memory types is short.

How short is that list?  Interestingly, Intel and Micron have different lists.  The Micron list, shown in this post’s graphic (click to enlarge), cites seven types: “Ram” (showing a vacuum tube), PROM, SRAM, DRAM, EPROM, NOR flash, and NAND flash.  Intel’s list adds magnetic bubble memory, making it eight.  (Definitions of these names appear in another Memory Guy blog post.)

The Memory Guy finds both lists puzzling in that they left out a number of important technologies.

For example, why did Intel neglect EEPROM, which is still in widespread use?  EEPROMs (or E²PROMs) are not only found in nearly every application that has a serial number (ranging from WiFi routers to credit cards), requires calibration (like blood glucose monitoring strips and printer ink cartridges), or provides operating parameters (i.e. the serial presence detect – SPD – in DRAM DIMMs), but they still ship in the billions of units every year.  In its time EEPROM was an important breakthrough.  Over the years EEPROM has had a much greater impact than has PROM.

And, given that both companies were willing to include tubes, a non-semiconductor technology, why did both Continue reading

Micron/Intel 3D XPoint Raises More Questions than Answers

Micron-Intel 3D XPoint Memory InternalsMicron and Intel hosted an event in San Francisco Tuesday, July 28, to introduce a new memory technology that they have named “3D XPoint”.  This technology was explained to be “up to 1,000 times faster, with 1,000 times the endurance of NAND flash” while being significantly cheaper than DRAM.

Some technical details:

  • 3D XPoint is a “Fundamentally Different Technology” than current memory types.  It’s an ReRAM that uses material property changes for bit storage where both DRAM and NAND use charge to store a bit
  • The chip currently stores 128Gb in two stacked planes of 64Gb each, storing a single bit per cell
    • Today’s densest production NAND flash chips store 128GB by using MLC, so this chip actually has twice as many bit cells as any production NAND flash
    • The companies do not see a clear limit to the number of planes they can stack, but are optimistic about this
  • The bulk mechanism can be used to store multiple bits on a single cell (MLC)
  • Today’s chip is made using a 20nm process, but can scale well past that
    • There is no clear limit of how far the technology can be scaled
  • It’s 1,000 times faster than NAND flash and offers 1,000 times NAND’s endurance
  • It’s 10 times as dense as today’s “Conventional Memory” (which I suppose to be DRAM)
  • This is not intended to replace either NAND or DRAM, but to coexist as a new memory layer between NAND and DRAM

The companies claim that other Continue reading


Jim Handy Objective Analysis Memory Market Research +1 (408) 356-2549 Jim.Handy (at) Objective-Analysis.com

Translate to:

Website Translation GTS Translation