3D XPoint

3D XPoint
Name	3D XPoint
Inventor	Intel, Micron Technology
Type	Non-volatile memory
Released	2017
Predecessor	NAND flash memory, DRAM

3D XPoint. It is a non-volatile memory technology developed through a joint venture between Intel and Micron Technology, announced in July 2015. The technology was positioned as a revolutionary new class of memory, bridging a significant performance gap between high-speed DRAM and higher-density NAND flash memory. Initial products leveraging this technology were brought to market under the brand names Intel Optane and Micron QuantX.

Technology overview

The fundamental innovation is based on a bulk material property change, rather than storing charge in a floating gate like traditional NAND flash memory. It utilizes a cross-point array structure where memory cells sit at the intersection of perpendicular word lines and bit lines, enabling dense stacking. This architecture allows individual bits to be accessed without needing to read or write an entire block of cells, a limitation inherent to NAND flash. The underlying mechanism involves switching the electrical resistance of a chalcogenide-based material between a high-resistance and a low-resistance state.

Development and history

The research collaboration between Intel and Micron Technology began years before the public unveiling at an event in San Francisco. The joint venture, IM Flash Technologies, operated a fabrication facility in Lehi, Utah, which was the primary production site for the memory chips. In 2018, Micron Technology exited the joint development, leaving Intel to continue sole development of the technology for the data center market. The first commercial product, a SSD branded as Intel Optane Memory, was launched in 2017, followed by persistent memory modules like Intel Optane Persistent Memory.

Comparison with other memory technologies

When compared to NAND flash memory, it offers vastly higher endurance, lower latency, and faster write speeds, though at a higher cost per bit. Its performance is slower than volatile DRAM but provides the critical advantage of data persistence without power. It also differs significantly from emerging technologies like Phase-change memory and Resistive random-access memory, though it shares some conceptual similarities. The technology was often contrasted with Storage-class memory, a category it helped to define for applications requiring a unique blend of speed and persistence.

Architecture and operation

The core structure is a three-dimensional checkerboard where memory cells are stacked in multiple layers, connected by vertical conductors. Each cell consists of a selector and a memory element based on a material stack whose composition was a closely guarded secret by Intel and Micron Technology. The write operation functions by applying a specific voltage pulse to change the cell's resistance state, while a different, lower voltage is used for reading. This cross-point design eliminates the need for transistors at each cell, enabling greater density compared to DRAM.

Applications and products

Primary applications targeted high-performance computing, enterprise data centers, and advanced client systems. Intel marketed its derivatives aggressively for use as accelerated caching drives, high-endurance data center SSDs, and as a persistent complement to DRAM in systems like the Intel Xeon platform. Specific products included the Intel Optane SSD DC P4800X and the Intel Optane Persistent Memory 200 series. It was also explored for use in in-memory databases, real-time analytics, and other workloads run on platforms from Dell EMC, Hewlett Packard Enterprise, and Lenovo.

Performance characteristics

Key performance metrics included latency measured in microseconds, a significant improvement over the millisecond-range latency of NAND flash memory. Endurance, measured in drive writes per day, was orders of magnitude greater than that of consumer 3D NAND SSDs. Bandwidth for both read and write operations was substantially higher than for traditional SATA or even NVMe SSDs based on NAND flash. These characteristics made it particularly suitable for write-intensive workloads in financial trading, scientific computing, and large-scale databases.

Category:Computer memory Category:Intel Category:Micron Technology Category:Computer storage technologies