The XL-FLASH non-volatile memory promises to be almost as fast as the DRAM volatile memory, yet its price should still be in the 3D NAND range. Kioxia claims the latency times are 10 times lower than traditional 3D NAND and the transfer speeds along with the IOPS are considerably improved, especially for small files and random read/write operations.
https://www.notebookcheck.net/Kioxia-and-Western-Digital-present-ultra-high-speed-XL-FLASH-memory-as-an-alternative-to-Intel-Optane.455335.0.html
From the translated presentation overview, it appears to be SLC with extra read/write HW, so data density is about 1/4 of a comparable consumer TLC setup.
It doesn't quite make the successful argument that this is somehow better than Samsung's approach, and it basically can only claim to be cheaper than 3D Xpoint.
Sounds good, for virtual memory.
It might equal Optane in storage form factors, but that doesn't show the full strength of the media.
Optane really shines on DIMMs. It's latencies are further 30x lower than the Optane in SSDs.
There is a better solution called HybriDIMM of Netlist with better performance and higher capacity and throughput/IO and last but not least compatible with existing RDIMM/LRDIMM interface without bios changes required.