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DDR3 memory standard bows

By Chris Mellor
June 27, 2007 12:00 PM ET - The new Double Data Rate 3 (DDR3) standard gives a big performance improvement and should reduce power compared with older memory schemes, according to the standards group that made it.

The standard is being put forth by the JEDEC Solid State Technology Association, once known as the Joint Electron Device Engineering Council, which is the standards arm of the Electronic Industries Alliance. JEDEC expects the new standard to be widely adopted. DDR3 is a standard for synchronous dynamic RAM (SDRAM) and specifies a 1.5-volt power supply. DDR1 drew 1.8 volts, and DDR2 drew 2.5 volts.

DDR2 clocked the memory bus at twice the memory-cell speed and thus traded off an increase in memory-cell latency against an overall increase in memory throughput. DDR3 clocks the memory bus at four times the memory-cell speed to make the same trade-off -- except it also sports lower power consumption. DDR3 has an 8-bit-wide prefetch buffer; DDR2's is 4 bit, and DDR1's is 2 bit. DDR3 should win out over DDR2 where large amounts of data have to be transferred in and out of memory.

"The DDR3 standard represents the culmination of countless hours of collaboration between memory device, system, component and module producers," said Joe Macri, director of technology at Advanced Micro Device Inc. and the relevant JEDEC group chairman. "This standard will permit emerging systems to achieve greater performance, storage and functionality, consistent with the needs of an increasingly information-intensive world community."

The DDR3 standard is intended to operate over a performance range of 800 to 1,600 MT/s (million transfers per second) and device densities of 512MB to 8GB in monolithic and stacked packages. These could dramatically increase RAM capacities in PCs and mobile phones, better supporting, for example, a move to 64-bit PCs.

DDR3 represents an extension of DRAM's applicability to a far richer multimedia world and wider range of intelligent electronic devices. "The DDR3 standard will serve as the linchpin for developing a new generation of memory solutions that address demands for both lower power and high performance," said Paul Fahey, a JEDEC board member and Intel Corp.'s platform memory operations director. "DDR3 will be an essential ingredient in future mobility platforms and those applications requiring the highest performance, such as video-on-demand, encoding and decoding, gaming, and 3-D visualization." These will span the gamut form servers, high-end PCs and workstations to mobile phones and other handheld devices.

JEDEC is completing publication and release of a range of DDR3-based memory modules, including registered Dual Inline Memory Modules (DIMM), unbuffered DIMMs, small-outline DIMMs and other module types and configurations intended for use in desktop, mobile and server computer systems, telecommunications, point-of-sale systems, and a wide range of other electronic products. Support devices have also been developed; these include registers, phase-locked loops and other interface devices optimized for use with the new technology.

All JEDEC standards are available online, at no charge, at

Reprinted with permission from Copyright 2012 IDG, all rights reserved.
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