Intel® Optane™ Persistent Memory

• Intel® Optane™ persistent memory (PMem) has some similarities with DRAM in the following ways; Packaged in DIMMS, resides on the same bus/channels as DRAM, and can act in the same way as DRAM storing volatile data.
• Where Intel® Optane™ persistent memory (PMem) differs with DRAM is that it offers many new and exciting features. PMem comes in much higher capacities than traditional DRAM. PMem modules come in 128GB, 256GB and 512GB capacities, vastly larger than DRAM modules that typically range from 4GB to 32GB, though larger capacities exist. PMem also can operate in a persistent mode storing data even without power applied to the module which comes with added security to keep the data safe. Although PMem modules are not quite as fast as DRAM modules, on a cost/GB basis and the ability to increase the capacity to beyond that of DRAM, the TCO story is greatly improved over DRAM.

While both Intel® Optane™ persistent memory (PMem) and Intel® Optane™ SSDs use the same Intel® Optane™ memory media, they are very different products. Intel® Optane™ persistent memory is in a DIMM package, operates on the DRAM bus, can be volatile or persistent, and acts as a DRAM replacement. Intel® Optane™ SSDs, on the other hand, are strictly used for fast storage residing in standard NAND package models (AIC, M.2, U.2, EDSFF,…), reside on the PCIe bus using the NVMe* protocol, are always persistent for storage reasons, and act as a fast storage replacement. Additionally, Intel® Optane™ SSDs differ from standard Intel® 3D NAND SSDs by offering; breakthrough performance at all (and differentiated at low) queue depths (up to 6x faster than NAND), consistently responsive under load (up to 63x faster than NAND under write pressure), high quality of service (up to 60x better than NAND), and very high endurance (up to 20x more total terabytes written than NAND).

An NVDIMM (non-volatile dual in-line memory module) is hybrid memory that retains data during an outage. NVDIMMs typically integrate non-volatile NAND flash with DRAM and a dedicated backup power on a single memory subsystem. While it does offer persistency, it is usually a more expensive system as you need just as much NAND storage as your DRAM module plus the addition of the battery backup sub-system. There is also a delay in saving and restoring states when an outage has occurred. Additionally, if the battery is not maintained or goes bad you lose the backup capability. With Intel® Optane™ persistent memory, you have instant persistency with no additional components needed, no worry about changing a battery, no additional storage necessary so your cost is lower, and no performance hit on restore.