Compared to traditional storage devices, such as a hard drive or SSD, Optane offers much smaller capacity, but at much faster speeds. Its operational latency (the delay when accessing data) is as low as 10 microseconds.
How and why Optane is used
Optane memory connects to the motherboard as an M.2 module.
Optane uses a technology called 3D XPoint, in which memory cells are stacked in a multi-planar configuration. It is used primarily in servers, or in machine learning computing clusters, which benefit from high-speed access to massive data sets too large to store in conventional RAM.
As of April 2019, Optane modules are available in capacities ranging from 16 GB to 512 GB.
In 2018, Intel also announced new Optane DC Persistent Memory, a type of memory that connects to a motherboard using a DRAM slot. While similar to RAM in the way it connects to a motherboard and the size of the memory modules, it differs from RAM in the way it retains data. RAM temporarily stores data and loses the data when the computer is turned off, but Optane DC Persistent Memory retains data when the computer is powered down. However, it has a higher latency than RAM, so it's not yet a replacement for RAM.
Intel has designed the Optane DC Persistent Memory to be used with the next generation of their Xeon processors and compatible motherboards.
Intel also offers "Optane SSD" modules, which combine 3D XPoint and NAND flash for a blend of speed, efficiency, and higher capacity.