The latency of high IHOPs is crazy.https://arstechnica.com/information-technology/2017/03/intels-first-optane-ssd-375gb-that-you-can-also-use-as-ram; "Intel announced today the first Optane-branded product using its new 3D XPoint memory: the catchily named Intel Optane SSD DC P4800X. It's a 375GB SSD on a PCIe card. Initial limited availability starts today, for $1520...". (Also posted in the SSDs - State of the Product? thread.)
"The P4800X can be used as a regular PCIe attached SSD, but Intel has developed something it calls "Memory Drive Technology" that allows the P4800X, when used in conjunction with an appropriate chipset and processor (which means you'll have to use a Xeon processor), can be used as if it were RAM. Optane's latency and bandwidth are both worse than that of DRAM, but the density is higher, and the price substantially lower."