Intel to demonstrate possible DRAM replacement

Intel Chief Technology Officer Justin Rattner plans to give the company's first public demonstration of its PRAM (phase-change RAM) technology at the Intel Developer Forum (IDF) conference, which starts Tuesday in Beijing.

PRAM is a type of non-volatile memory being developed by Intel and several other companies. The prototype chips are seen as a replacement for flash memory and, perhaps, DRAM (dynamic RAM). Unlike DRAM, non-volatile memory like flash can store memory when a device's power is turned off, but flash memory chips write and read data more slowly than DRAM, have less capacity, and are also more expensive.

"We're thinking phase change is looking promising and we're going to go into production with that part in the second half of the year," Rattner said during an interview ahead of IDF.

PRAM is based on chalcogenide glass, which can be altered using the heat generated by an electric current. Heat changes the physical structure of the glass to either a crystalline or amorphous state. Each of these states has a distinct electrical resistance that is used to represent the ones and zeroes needed to represent stored data in binary terms.

PRAM looks set to offer better read-write speed and durability than flash memory, which works by trapping electrons in a memory cell. Over time, electrons inevitably become trapped in these cells and can no longer be removed, rendering the memory chip useless.

"It's not clear there's actually a wear out mechanism because your just moving this material, chalcogenide, between phase states," Rattner said. "Inherently, that's not a destructive process."

Intel and other companies are counting on PRAM to replace both NOR and NAND flash memory to generate the demand required to produce the new memory chips in volume, and drive down costs.

Flash memory is used in cell phones and other mobile devices, but can also be used in PCs. Flash is also at the heart of Intel's Robson flash memory cache technology. Robson, and similar technologies, like hybrid-disk drives, use flash to improve system performance. Robson and hybrid-disk drives try to anticipate which files will be required by a user and load them into the flash-memory cache, reducing the number of times information must be read off the hard disk.

PRAM could also be used in this way, and Intel is investigating whether the chips could take on an even bigger role. "Ultimately we have to answer the question, is phase-change memory a replacement for DRAM? It seems to have the performance characteristics," Rattner said.

Even if PRAM proves to be a practical replacement for DRAM, that's doesn't necessarily mean that PRAM will replace it completely. "Is it a new level in the hierarchy? Or will DRAM move into more of a new level of the cache hierarchy and phase change will actually be the main memory as we think of it today?" Rattner said.