Introduction

DDR's origins

Back in October, AMD introduced us to its latest technologies for the Socket A platform: the 266MHz front-side bus, and its DDR SDRAM chipset, AMD-760. At that time, we witnessed a 10% performance gain over a similarly equipped 200MHz Athlon system running with conventional PC133 SDRAM. Ten percent may not sound like much at first, but the potential for even greater margins of performance as CPU clock speed increases built much anticipation for the new DDR platform.

Fast-forward a few weeks to Comdex 2000 in sunny Las Vegas, Nevada. During a meeting with VIA Technologies we're introduced to their DDR chipset for Intel's Pentium III processor, Apollo Pro266, and another newcomer, the KT133A chipset. Based largely on VIA's existing KT133 chipset, KT133A added support for the newer 266 front-side bus that had just been launched by AMD. While representatives from VIA were focused on promoting Apollo Pro266, we quietly mentioned reports from engineers at ABIT indicating that KT133A could be a surprising performer for the company.

Of course, by now we all know how this story unfolded. While AMD's 760 chipset was a terrific performer, stability issues at 266MHz with AMD's launch partner for AMD-760, Gigabyte Technology, led to product delays and initial shipments were limited to just 200MHz operation with PC1600 DDR SDRAM. At 200MHz, hardly any of the performance gains we'd witnessed with the 760 chipset in October were realized, leaving a disappointing feeling in our wallet. In contrast, our performance results with KT133A were quite impressive at 266MHz, easily rivaling our test results from October, and best of all KT133A used good old PC133 SDRAM.

KT266: VIA's Socket A DDR solution

However, with VIA's firm commitment to DDR SDRAM, a product that supports the technology for the AMD platform was in the works: KT266.

KT266 system running with 256MB memory/GeForce2 Ultra

A closer look at the northern end of the motherboard

Unlike KT133A, VIA's KT266 chipset is based on an entirely new architecture. Besides support for bus speeds of 200MHz and 266MHz, KT266 adds one unique feature that isn't present on AMD-760: support for both PC133 SDRAM and PC2100 DDR SDRAM. In fact, in our tests today we reveal performance results with Shuttle's AK32 motherboard, which supports both memory types seamlessly.