I believe that HPE was also the division of HP behind the memristor that unfortunately has gone nowhere commercially. They had some truly innovative ideas for non Von Neumann architectures using the memristor, but you need to get the fundamental components working at scale first.
HPE is still doing some research. Gen-Z superficially looks like it was the child of their "The Machine" research efforts. The memristor itself was supposed to be part of "The Machine" but they never were able to produce them at scale for production as you mentioned. HPE so far has moved their persistent memory technology to something else (not sure what they're doing there but it seems to be different than Intel/Micron 3D Xpoint).
HPE has at least done something with the SGI acquisition as they used the acquired technology for the SuperDome Flex. Unfortunately HPE is not advertising any socket count beyond 32 on the SuperDome Flex systems due to the need for additional hops in the interconnect. They are still selling larger up to 256 socket boxes leveraging Broadwell. Memory capacity is one reason why the older system is still offered.
Dual Opteron 6376, 96 GB DDR3, Asus KGPE-D16, GTX 970
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Core i7 3930K@4.2 Ghz, 32 GB DDR3, GA-X79-UP5-Wifi
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