November 2001

Speedy Delivery

Hardware

By Erika Jonietz

Chips inside today's computers process data with ferocious speed. But a computer's performance is limited by how fast data travels between, say, the memory and logic chips. Buses, the devices that move data between computers' components, are notorious bottlenecks. But their reputation could be on the mend, thanks to a consortium of chip and computer-equipment makers created to commercialize a lightning-fast bus technology from Advanced Micro Devices.

The bus, which AMD calls HyperTransport, enables data transfer rates of up to 12.8 gigabytes per second, about 50 times faster than the current standard. While it's hard to quantify the resulting improvement in computer performance, Linley Gwennap, principal analyst at the Linley Group in Mountain View, CA, says that such faster buses are critical to reaping the benefits of the next generation of superfast microprocessors. Today's buses are like a one-lane bridge: if data is going out of a chip, nothing can come in. AMD's new buses provide both an inbound and an outbound link. "You wind up with a mini-network of chips on the motherboard. It allows you to send stuff incredibly fast," says David Rich, general manager of API NetWorks, a consortium member based in Concord, MA.

In addition to its blazing speed, HyperTransport has lower power requirements than today's buses, making it a natural for personal digital assistants and laptops. But the technology's first applications will be in high-performance computing. Graphics-chip maker and consortium member NVidia, for example, incorporated the bus into its chips for Microsoft's Xbox, a graphics-intensive video game system set to ship this month in the United States. Cisco Systems, also in the consortium, expects to ship network routers using the buses within a year. At least when it comes to computers, you won't have to wait for the bus anymore.