The Optane DIMMs will come in DDR4 module sizes and will also feature NVMe-like capacities of at least 512 GB. These will improve data caching without the need of an SSD, speeding up load times in applications and games. Estimated cost is around US$88.
https://www.notebookcheck.net/Intel-Optane-DIMMs-to-hit-the-market-in-second-half-of-2018.263836.0.html