DDR Information and Links Page
DDR PC2100 is Fast
DDR (Double Data Rate) SDRAM memory is an evolutionary product built upon the foundation of current PC100/PC133
memory technology. Unlike SDRAM memory that supports one operation per
the computer's clock cycle, DDR SDRAM memory can do two operations per
clock cycle, thereby doubling the memory bandwidth over the corresponding
single-data-rate SDRAM. --http://www.kingston.com/memory/ddr
DDR Memory is a new type of SDRAM that is able to double the read / write speed of the previous generation of SDRAM memory. There are currently 2 speeds offered - 200MHz (Called PC1600 - because it is able to transfer 1600Mbit / sec) and the newer 266MHz (Called PC2100 - because it is able to transfer 2100Mbit / sec). These DIMMs are 184 Pin in size and are not interchangeable with older SDRAM modules. DDR memory can only be used in systems designed specifically for DDR memory --http://www.shopsite.com/html/1stchoicememory/page770.html
. Double data rate memory is a key element in ensuring that memory keeps pace with the ever-increasing performance of microprocessors. By doubling the memory bandwidth over current generation SDRAM solutions, DDR can provide a cost-effective, high-performance main memory solution that does not require a significant development or manufacturing investment, while maintaining a cost structure consistent with synchronous DRAMs. DDR devices and modules are well-suited for a broad range of applications, especially the workstation and server markets, where the high module density and device architecture can meet the performance and reliability demands of these products. "IBM is committed to the success of DDR as a mainstream memory solution," said James Karl, Memory Marketing and Applications Manager, IBM Microelectronics. "As we have previously done with PC100 and PC133 registered dual in-line memory modules, we are continuing to provide industry support for the development of system solutions using the latest industry-standard memory technology." DDR memory technology has been defined and standardized by the Joint Electron Devices Engineering Council (JEDEC) as the next-generation memory solution, following the mainstream PC100 and PC133 SDRAM products that are currently utilized in most main memory applications. This technology is intended to facilitate adoption in a wide range of products, and to be offered in both device and module form from all major suppliers. Predominant device speed grades of PC200 and PC266 have already been standardized by JEDEC, permitting the production of 184-in dual in-line memory modules (DIMMs) that offer peak bandwidths of 1.6GB per second and 2.1GB per second, respectively. Advanced Memory International (AMI2), an association formed to provide industry leadership direction for users of new DRAM technology, has announced support for the new 184-pin DIMM standard. "AMI2 is promoting the 184-pin DDR DIMM family as the mainstream module offering for DDR memory, and the efforts by IBM and other leading DDR device suppliers will help to ensure the rapid adoption of this new technology," said Desi Rhoden, President and CEO of AMI2. "The Web site being announced by IBM is a critical element both in ensuring consistency between memory suppliers, as well as permitting systems to implement DDR designs with the knowledge that a high degree of quality and compatibility will exist in the industry." DDR devices and modules are intended to provide a 2X increase in memory bandwidth over earlier PC100 and PC133 SDRAM solutions. This performance improvement is obtained by utilizing both edges of the memory clock in sending and receiving data — hence the source of the name "double data rate" SDRAM. To better describe the performance of these new module offerings, which are all 8 bytes (64 or 72 bits in width), naming conventions of PC1600 and PC2100 (for 8-byte DIMMs using PC200 and PC266 devices, respectively) have been adopted. These new speed grades define the module performance, in MB/s (million bytes per second) that will be obtained when using the new memory modules. For comparison, mainstream PC100 (SDRAM) modules offer a performance of 800 MB/s, and Rambus RIMMs are expected to offer performance sorts of up to 1600 MB/s. The 184-pin DDR registered DIMM family has already been standardized by JEDEC, and is expected to be used in a wide range of applications from PC desktop to servers and workstations. These DIMMs offer reduced system loading versus unbuffered DIMMs, by including on-board registers for signal redrive and a PLL (phase locked loop) for clock regeneration and distribution. With this added circuitry, the DIMMs permit the design of higher density systems — since these DIMMs require a reduction in loading for the address, command and clock circuitry. In addition, single cycle operation of the address and command bus is possible, permitting random address activation in two clocks, which matches the data transfer rate and maximizes the memory effective bandwidth. In general, the registered DIMMs will be utilized in applications with four or more DIMM sockets, with total system density of 64 GB or more. "Reliance has adopted DDR as the optimal main memory follow-on to existing SDRAM solutions," said David Pulling, Vice President of Marketing and Sales for Reliance Computer. "The competitive cost structure, performance advantages versus competing solutions and broad industry support will help to ensure the success of this technology in our customers' applications. IBM is providing an invaluable service to the industry in the design and support of these new DDR modules." The new DDR Web site is modeled on a similar site introduced by IBM in March of 1999, in support of PC133 registered DIMMs. The earlier site, which was a key aspect of IBM's first industry-wide "memory enablement" effort, has been widely utilized by DRAM designers, module developers, and system producers alike, and served as a communication channel for the transfer of design information and the resolution of technical questions. As with the earlier site, information will be added as module and system design experience progresses — and the site is intended to serve as a conduit for information leading to broad industry introduction. In announcing availability for this new Web site, IBM has posted development information for DDR registered DIMMs which includes (and will include) information such as: A 184-in DDR registered DIMM design specification — intended for
both memory and system developers --http://www-3.ibm.com/chips/news
The objective of the Intel® DDR validation program is to verify DDR SDRAM compliance to the Intel® DDR specifications and performance of DDR DIMM and SO-DIMM modules in Intel® reference systems, so as to provide a guideline for memory compatibility with Intel® chipsets. This validation will be performed on a small sample of components and modules and is intended to demonstrate supplier design and manufacturing capability. The validation process uses standardized procedures and methodologies documented in the Intel® DDR Validation Specification. For a copy of the specification, contact the Intel Validation Program manager. This is not intended to replace the normal product qualification process. Validation is performed at the component and Registered DIMM/Unbuffered
DIMM/SO-DIMM levels and the results are posted below:
--http://developer.intel.com/technology/memory/ddr
Compaq Delves Into DDR Memory Ashlee Vance, IDG News Service Compaq Computer has unveiled a new desktop PC designed to give users an extra graphics punch. Running on an Advanced Micro Devices processor, the new PC uses DDR, an emerging high-speed memory type. Compaq also announced a new low cost desktop PC. The new Presario units, announced Wednesday, are available immmediately direct from Compaq's Consumer Web site. The Presario Series 7000z model 7QS, which is priced from $1299, is Compaq's first desktop to include the DDR (double data rate) SDRAM memory technology, a company spokesperson says. DDR SDRAM doubles the data transfer rate in a chip set to give users an edge when working with graphic-intensive applications or creating digital content. The memory standard is being promoted by AMD, Via Technologies, and several memory makers as a cheaper alternative to RDRAM (Rambus DRAM). RDRAM is based on proprietary technology from a memory technology design company Rambus. The 7QS is offered with AMD's Athlon processor at speeds ranging from 1 GHz to 1.2 GHz. Compaq will also include MyMovieStudio video editing software and DVD-R technology for writing information onto DVDs.
DDR Memory for Graphics Cards The fastest graphics chip can be crippled if it can't move the data from video memory to the graphics chip and back. One solution is to have multiple rendering engines, each with its own dedicated pool of memory. A more elegant solution is simply to use faster memory. We took a look at a pair of graphics cards that are among the first to use DDR memory: the Creative Labs 3D Blaster Annihilator Pro ($300 street) and the Hercules 3D Prophet DDR-DVI ($300 street). Using the new nVidia GeForce 256 graphics accelerator chips, both cards proved to be among the fastest consumer-level 3-D graphics cards available today. What card you buy depends heavily on how you value the trade-off between software and hardware features. On the one hand, business users will like the DVI output on the Prophet, but the Annihilator Pro's E-Color tools are also useful for heavy graphics users. The Creative Labs 3D Blaster Annihilator Pro offers fewer hardware features than the Prophet but more software amenities. Like the Prophet, it ships with 32MB of 6-ns (183-MHz) DDR SDRAM. The Annihilator Pro has only a single VGA output connector, although it does have an internal connector for a DVI daughtercard (currently not available). The Annihilator Pro offers essentially identical performance to the Prophet; the key difference was in the Expendable test scores, which may be attributable simply to the difference in driver revisions. The card's 2-D performance was also neck and neck with that of the Prophet. What's compelling about the Creative Labs card is the bundled software. On the gaming side, the card ships with the full version of Need for Speed: High Stakes and a limited version of Evolva, an action game. Of more interest to graphics and business users are the Colorific and 3Deep color-balancing and color-matching tools from E-Color. There's also WinDVD, a capable if limited software DVD player. The overall DVD image quality is comparable to that of the Prophet: quite good, but with minor flaws during fast camera movement. The Hercules 3D Prophet DDR-DVI (now owned by Guillemot International) ships with 32MB of 6-ns DDR SDRAM. The card also has a DVI interface for use with the new generation of flat-panel displays and digital monitors. Rounding out the output options is an S-Video TV output and a VGA connector. The DVI output works well with the ViewSonic VP-181 digital flat-panel display. TV output is more limited, forcing the computer display to run at the same resolution and refresh rate as a TV monitor (800-by-600 maximum resolution at 60 Hz). The control panel allows extensive customization of 3-D features and performance but is buried in a somewhat confusing interface. The 3D Prophet is a nimble performer, coming through with some of the highest scores we've seen on our 3D WinMark 2000. It was no slouch in the 2-D arena either, posting high scores on our ZD Business Winstone 99 and ZD Content Creation Winstone 2000 benchmark tests. Of course, this card is aimed squarely at the high-end gaming market. It ran the Quake III Time Demo at close to 57 frames per second (at 1,024-by-768, with 32-bit color). Its fps rate while running Expendable at that resolution was also quite good. The only software bundled with the 3D Prophet consists of game demos and Xing Technology's software DVD playback utility. DVD playback with the 3D Prophet is good, though we saw some blurring in scenes with exaggerated motion
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