IBM Announces Phase-Change Memory: Lower Cost, Faster & More Durable than NAND Flash Memory


In June 2011 IBM announced that it produced phase-change memory (PCM) chips that could store two bits of data per cell without data corruption problems over extended periods of time. This significant improvement advanced the development of low-cost, faster and more durable memory applications for consumer devices, including mobile phones and cloud storage, as well as high-performance applications, such as enterprise data storage.

"With a combination of speed, endurance, non-volatility and density, PCM can enable a paradigm shift for enterprise IT and storage systems within the next five years. Scientists have long been searching for a universal, non-volatile memory technology with far superior performance than flash – today’s most ubiquitous non-volatile memory technology. The benefits of such a memory technology would allow computers and servers to boot instantaneously and significantly enhance the overall performance of IT systems. A promising contender is PCM that can write and retrieve data 100 times faster than flash, enable high storage capacities and not lose data when the power is turned off. Unlike flash, PCM is also very durable and can endure at least 10 million write cycles, compared to current enterprise-class flash at 30,000 cycles or consumer-class flash at 3,000 cycles. While 3,000 cycles will out live many consumer devices, 30,000 cycles are orders of magnitude too low to be suitable for enterprise applications" (, accessed 07-01-2011).

Like high-density NAND flash memory used in solid state drives (SSDs). phase-change memory is nonvolatile.  However, unlike NAND flash, PCM memory does not require existing data be marked for deletion prior to having new data written to it — a process known to as an erase-write cycle. Erase-write cycles slow NAND flash performance and, over time, wear it out, giving it a lifespan that ranges from 5,000 to 10,000 write cycles in consumer products, and up to 100,000 cycles in enterprise-class products.

"As organizations and consumers increasingly embrace cloud-computing models and services, ever more powerful and efficient, yet affordable storage technologies are needed, according to Haris Pozidis, manager of memory and probe technologies at IBM Research" (, accessed 07-01-2011).

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