Evolution to DDR SDRAM Memory

As more and more sophisticated applications and faster components become available and contend with memory resources the bandwidth for memory has increasingly been reduced to a sheer bottleneck. Whilst, major manufacturers in their consortiums have been touting differing standards, we have not had a solid offering until now. The latest and greatest of them currently leading the pack is the new Double Data Rate (DDR) SDRAM. You may have heard the term RDRAM this is Intel's version of memory it decided to implement and push heavily for the Intel Pentium 4 platform in partnership with RAMBUS, although RDRAM is not a bad alternative, the availability, lack of co-operation and cost of implementation has restricted it's implementation across the industry spectrum. In a quest to meet the performance requirements of new and emerging high-bandwidth applications and technologies, and industry-wide effort involving JEDEC and industry leaders from over 280 manufacturers (TeamDDR) and users, helped define a new, but evolutionary, extension to the existing SDRAM memory technology. The mission was a simple one: create an evolutionary form of memory that would take advantage of existing manufacturing test and equipment processes and would meet the high performance and low power needs of a new generation of speed and memory hungry graphic processors, notebooks, desktops, workstations and servers. The culmination of this effort is DDR SDRAM or PC-1600/PC-2100, which is now in volume production today. DDR SDRAM provides a natural way of integrating the newest level of memory bandwidth into mainstream markets from notebook to multi-processor servers. As we can see below, PC-1600 provides a peak data bandwidth of 1.6GB/sec and PC-2100 provides a peak data bandwidth of over 2.1GB/sec - twice that of today's PC-133 SDRAM.

DDR SDRAM can be placed on the familiar 184-pin DIMM (dual in-line memory module). Thus, computer manufacturers, system integrators, and end-users will benefit by saving time and expense during installation of memory onto the system motherboard. Furthermore, DDR SDRAM memory module manufacturers can broadly supply memory modules because of the enormous similarities in manufacturing to that of existing SDRAM technologies including equipment, packaging, design methodology, and low-cost components. The motherboard connector used for both SDRAM and DDR SDRAM DIMMs has a straight plug-in design, requiring a low insertion force, and is flanked by robust latch towers for module alignment and dual ejectors for easy module removal. This connector can be used for desktop, workstation, and server computer designs. For the burgeoning small form factor computers, DDR DIMM manufacturers will be able to use a newer 200-pin Dual Small Outline DIMM (SO-DIMM) low profile connector that measures only 20mm high and only 0.65 mm long. SO-DIMMs offer convenient add-on memory expansion and upgradeability for future memory technologies.

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