A NVDIMM (pronounced "en-vee-dimm") or non-volatile DIMM is a type of persistent

random-access memory Random-access memory (RAM; ) is a form of Computer memory, electronic computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A random-access memory device allows ...

for computers using widely used

DIMM A DIMM (Dual In-line Memory Module) is a popular type of memory module used in computers. It is a printed circuit board with one or both sides (front and back) holding DRAM chips and pins. The vast majority of DIMMs are manufactured in compl ...

form-factors.

Non-volatile memory Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data. Non-volatile memory typ ...

is memory that retains its contents even when electrical power is removed, for example from an unexpected power loss, system crash, or normal shutdown. Properly used, NVDIMMs can improve application performance and system crash recovery time. They enhance

solid-state drive A solid-state drive (SSD) is a type of solid-state storage device that uses integrated circuits to store data persistently. It is sometimes called semiconductor storage device, solid-state device, or solid-state disk. SSDs rely on non- ...

(SSD) endurance and reliability. Many "non-volatile" products use volatile memory during normal operation and dump the contents into non-volatile memory if the power fails, using an on-board backup power source. Volatile memory is faster than non-volatile; it is byte-addressable; and it can be written to arbitrarily, without concerns about wear and device lifespan. However, including a second memory to achieve non-volatility (and the on-board backup power source) increases the product cost compared to volatile memory. There are many emerging non-volatile memories in development and a few that have been launched including

Magnetoresistive RAM Magnetoresistive random-access memory (MRAM) is a type of non-volatile random-access memory which stores data in magnetic domains. Developed in the mid-1980s, proponents have argued that magnetoresistive RAM will eventually surpass competing techn ...

(MRAM), Intel's

3D XPoint 3D XPoint (pronounced ''three-D cross point'') was a discontinued non-volatile memory (NVM) technology developed jointly by Intel and Micron Technology. It was announced in July 2015 and was available on the open market under the brand name Opt ...

(discontinued in 2022),

Nano-RAM Nano-RAM is a proprietary computer memory technology from the company Nantero. It is a type of non-volatile memory, nonvolatile random-access memory based on the position of carbon nanotubes deposited on a chip-like substrate. In theory, the small ...

based on

carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with a diameter in the nanometre range ( nanoscale). They are one of the allotropes of carbon. Two broad classes of carbon nanotubes are recognized: * ''Single-walled carbon nanotubes'' (''S ...

s. The goal of this technology is able to scale cost-effectively scale out so persistent memory could replace DRAM as the main system memory in enterprise systems.

Types

There are three types of NVDIMM implementations by

JEDEC The Joint Electron Device Engineering Council (JEDEC) Solid State Technology Association is a consortium of the semiconductor industry headquartered in Arlington County, Virginia, Arlington, United States. It has over 300 members and is focused ...

Standards org: *NVDIMM-F: DIMM with flash storage. System users will need to pair the storage DIMM alongside a traditional DRAM DIMM. While there's no official standard, NVDIMM-F type of modules have been available since 2014. *NVDIMM-N: DIMM with flash storage and traditional DRAM on the same module. The computer accesses the traditional DRAM directly during system runtime. In the event of a power failure, the module copies the data from the volatile traditional DRAM to the persistent flash memory, and copies it back when power is restored. It uses a small backup power source for the module while the data in DRAM is being copied to the flash storage. * NVDIMM-P: specification fully released by JEDEC in February 2021. It enables computer main memory to be persistent, using

persistent memory Persistent may refer to: * Persistent data * Persistent data structure * Persistent identifier * Persistent memory * Persistent organic pollutant * Persistent Systems, a technology company * USS ''Persistent'', three United States Navy ships ...

technology and can share the

DDR4 Double Data Rate 4 Synchronous Dynamic Random-Access Memory (DDR4 SDRAM) is a type of synchronous dynamic random-access memory with a high bandwidth ("double data rate") interface. Released to the market in 2014, it is a variant of dynamic rando ...

DDR5 Double Data Rate 5 Synchronous Dynamic Random-Access Memory (DDR5 SDRAM) is a type of synchronous dynamic random-access memory. Compared to its predecessor DDR4 SDRAM, DDR5 was planned to reduce power consumption, while doubling bandwidth. The ...

DIMM interconnect with DRAM DIMMs. Non-Standard NVDIMM implementations: * NVDIMM-X: DDR4 DIMM with NAND Flash storage and volatile DRAM on the same module, developed by Xitore. As of 2024, most NVDIMMs used

NAND flash Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...

as the non-volatile memory. Emerging memory technologies aim to achieve persistency without a cache or two separate memories. Intel and Micron have released in 2017, then discontinued in 2022, the

PCM Pulse-code modulation (PCM) is a method used to Digital signal (signal processing), digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio application ...

technology, but it never was sold in DIMM format, contrary to announcements.

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

and Viking Technology have announced an NVDIMM-N product based on the

ReRAM Resistive random-access memory (ReRAM or RRAM) is a type of non-volatile (NV) random-access memory, random-access (RAM) computer memory that works by changing the resistance across a dielectric solid-state material, often referred to as a memrist ...

technology, but it never reached the market. Similarly, in 2015,

Samsung Samsung Group (; stylised as SΛMSUNG) is a South Korean Multinational corporation, multinational manufacturing Conglomerate (company), conglomerate headquartered in the Samsung Town office complex in Seoul. The group consists of numerous a ...

and

Netlist In electronic design, a netlist is a description of the connectivity of an electronic circuit. In its simplest form, a netlist consists of a list of the electronic components in a circuit and a list of the nodes they are connected to. A netwo ...

announced a NVDIMM-P product, possibly based on Z-NAND.

Backup power

NVDIMMs evolved from the BBU (battery backed up)

, which used a backup battery to sustain power to a volatile memory for up to 72 hours. However, batteries are disfavored in computer components because they have a limited lifespan, they may be regarded as

hazardous waste Hazardous waste is waste that must be handled properly to avoid damaging human health or the environment. Waste can be hazardous because it is Toxicity, toxic, Chemical reaction, reacts violently with other chemicals, or is Corrosion, corrosive, ...

, and may contain

heavy metals upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...

which violate

RoHS The Restriction of Hazardous Substances Directive 2002/95/EC (RoHS 1), short for Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment, was adopted in February 2003 by the European Uni ...

compliance. When the module includes non-volatile memory, backup power is required for only a short time after the computer's main power fails, while the module copies the data from volatile to non-volatile memory. Therefore, modern NVDIMMs use on-board supercapacitors to store energy.

Interface

A few server vendors still make products using the

DDR3 Double Data Rate 3 Synchronous Dynamic Random-Access Memory (DDR3 SDRAM) is a type of synchronous dynamic random-access memory (SDRAM) with a high Bandwidth (computing), bandwidth ("double data rate") interface, and has been in use since 2007. ...

interface to the computer, but standardization work in 2014 and 2015, such as at

and

ACPI Advanced Configuration and Power Interface (ACPI) is an open standard that operating systems can use to discover and configure computer hardware components, to perform power management (e.g. putting unused hardware components to sleep), auto con ...

, was based on the

interface.

OS support

Windows Server 2016 Windows Server 2016 is the eleventh major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was developed alongside Windows 10 and is the successor to the Windows 8.1-based ...

added native support for NVDIMM-N.

Uses

The BBU DIMM was originally designed for use as the cache of

RAID RAID (; redundant array of inexpensive disks or redundant array of independent disks) is a data storage virtualization technology that combines multiple physical Computer data storage, data storage components into one or more logical units for th ...

HBAs (host bus adapters) or systems, to enable data in the cache to survive a power failure. NVDIMMs have moved beyond RAID applications into fast storage appliances or in-memory processing for the

data center A data center is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and storage systems. Since IT operations are crucial for busines ...

and

cloud computing Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for ...

References

External links

Memory that never forgets

NVDIMM improve SSD enduranceMemory And Processor Advances Redefine Digital TechnologyNon-Volatile DIMMs and NVMe Spice Up The Flash Memory Summit

NVDIMM Electronic Solution
''(German)'' {{DEFAULTSORT:NVDIMM Non-volatile random-access memory