[mapt]

This was always a strange point of contention - Intel denied using memristors. I assume there were some sort of patent or trademark issues.

WP:

"Development of 3D XPoint began around 2012.[8] Intel and Micron had developed other non-volatile phase-change memory (PCM) technologies previously;[note 1] Mark Durcan of Micron said 3D XPoint architecture differs from previous offerings of PCM, and uses chalcogenide materials for both selector and storage parts of the memory cell that are faster and more stable than traditional PCM materials like GST.[10] But today, it is thought of as a subset of ReRAM.[11] According to patents a variety of materials can be used as the chalcogenide material.[12][13][14]

3D XPoint has been stated to use electrical resistance and to be bit addressable.[15] Similarities to the resistive random-access memory under development by Crossbar Inc. have been noted, but 3D XPoint uses different storage physics.[8] Specifically, transistors are replaced by threshold switches as selectors in the memory cells.[16] 3D XPoint developers indicate that it is based on changes in resistance of the bulk material.[2] Intel CEO Brian Krzanich responded to ongoing questions on the XPoint material that the switching was based on "bulk material properties".[3] Intel has stated that 3D XPoint does not use a phase-change or memristor technology,[17] although this is disputed by independent reviewers.[18]

According to reverse engineering firm TechInsights, 3D XPoint uses germanium-antimony-tellurium (GST) with low silicon content as the data storage material which is accessed by ovonic threshold switches (OTSes)[19][20] made of ternary phased selenium-germanium-silicon with arsenic doping.[21][22]"