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Micron's Upcoming Samurai DDR Chipset - First Looks

Introduction

While Intel pushes their newest RDRAM supported chipsets, the i820 and i840, other chipset manufacturers obviously see the opportunity to provide lower priced alternatives. VIA enjoyed Intel's i820 launch delays, given that VIA provided the only 133FSB alternative for Intel's Coppermine CPU. They were able to make it into some of the top tiers product offerings because of Intel's launch disaster. Now that Intel has finally launched their i820 mainstream chipset they are still faced with the RDRAM price dilemma. RDRAM is nearly impossible to get a hold of, and once you do find it you have to shell out big bucks for it. Intel then introduced their MTH (memory translator hub) so motherboard makers could offer a lower cost platform based on the i820 (details on the MTH can be found Intel's New CC820 Motherboard Review ). Motherboards with the MTH implemented in to the design provide the support of the lower priced PC100 SDRAM. Unfortunately, along with the lower cost memory comes a huge performance decrease (-15%). Even an i820 platform outfitted with high priced RDRAM memory doesn't really offer much of a performance advantage over 440BX based boards (details on the i820 chipset can be found Intel's i820 Chipset Review ). Well I am happy to see that Micron also recognizes these problems and is working on their new upcoming chipset code named 'Samurai DDR'.

The 'Samurai DDR' Chipset

Micron is known for both their memory manufacturing and x86 computer platforms. They have been shipping their Samurai (non-DDR) chipset for some time now in their high-end workstation product line. Micron has made some improvements to this chipset, which is code named 'Samurai DDR'. This chipset supports DDR SDRAM, 4x AGP, 133 FSB (front-side bus), and also a 66 MHz 64-bit wide PCI bus (also found on Intel's higher-end i840 based platforms). Many of you that have been following our graphics board reviews have heard mention of DDR memory on NVIDIA's GeForce product. It makes a lot of sense to support this same memory technology in a motherboard chipset. DDR stands for Double Data Rate. Its name tells it all, DDR memory provides twice the data rate as good old standard SDRAM. How does DDR memory get so much more bandwidth? Easy. SDRAM is only able to pass data on the rising edge of a clock cycle while DDR SDRAM can pass data on both the rising and falling edge thus twice the throughput. Here is a table that will compare the memory bandwidth across several platforms.

Chipseti440BXVIA Apollo Pro 133 Plusi820 RDRAMi840 RDRAMSamurai DDR PC200Samurai DDR PC266
FSB MHz100 MHz133 MHz133 MHz133 MHz100 MHz133 MHz
Bandwidth800 MB/s1064 MB/s1.6 GB/s3.2 GB/s1.6 GB/s2.1 GB/s

Intel's high-end i840 chipset is the only chipset that offers a higher memory bandwidth than the Micron's DDR chipset, however, the i840 is still haunted by RDRAMs higher latencies. Micron is working hard to release this chipset sometime near the middle of 2000 and has also licensed some of their technology to VIA.