Dual-Core Chips Shift Performance FocusDual-Core Chips Shift Performance Focus

With the race for dominance in processor clock speed over, or at least waning, the pursuit for overall performance gains through architectural enhancements is officially beginning. Back-to-back demonstrations of dual-core processor implementations by Advanced Micro Devices Inc. last week and by Intel at its Developer Forum this week are kicking things off.

"For many years, performance enhancements, which have been dramatic, were achieved through scaling frequency or megahertz or gigahertz," says Frank Spindler, VP of Intel's corporate technology group and director of its industry technology programs. "We're shifting into providing different types of usage environment technologies in our silicon to achieve performance gains."

Dual-core processors reside on a single chip and can run at lower clock frequencies, leading to cooler operations and performance parity or even gains over single-core chips. AMD last week demonstrated how a four-way Hewlett-Packard server using its Opteron dual-core chip effectively turned the machine into an eight-way system with no hardware changes. HP calls dual-core processing a game-changing technology that will lead computer makers to offer a wider variety of systems aimed at specific markets.

After years of steadily building up processor performance with incremental clock-speed increases, AMD and Intel have been trying to wean systems makers and consumers off of clock speed, urging them instead to look at total performance as an indicator of leading-edge technology. The move has taken several forms in the past couple of years, including a decision by both chipmakers to create new product names for their chips that didn't include clock speed.

"This is changing the dynamics of the industry," says Ben Williams, director of the server and workstation business segment at AMD. "Think about all the knobs we can turn to increase performance or productivity--core speed, levels of [on-chip memory] cache, I/O architectures, multiple cores. The key metric going forward is performance per watt per dollar."

Paul Horn, senior VP and head of research at IBM, estimates that annual gains in clock speed that have averaged around 35% in the past from now on will be between 10% and 15%, resulting in "a sea change in the way processors are designed."

Analysts agree that architectural enhancements have the potential to actually outpace the rate of performance gains that have been realized in the past through increasing a processor's speed. For example, pushing a Pentium 4 from 2 GHz to 3 GHz clock speed provides a 50% speed improvement but yields only a 25% improvement in overall performance, says Nathan Brookwood, an analyst at Insight 64. Adding a second core would increase performance by 90% without increasing clock speed, he says.

Still, taking full advantage of the performance gains won't be automatic. "The development community will be challenged to create sets of applications that take full advantage," Spindler says.

The dual-core announcements show that Intel and AMD are virtually neck-and-neck in bringing out new technologies, differentiating themselves with enhancements such as Intel's hyperthreading and AMD's hypertransport technologies, which enable multiple applications to run simultaneously, says Dean McCarron, an analyst at Mercury Research.

Intel declines to say which processor will showcase its dual-core technology this week, though it's generally believed that Intel is furthest along with designing a dual-core Itanium. If the company were to demonstrate a dual-core Xeon, its more popular chip, Brookwood says, "it would suggest Intel is further along with its strategy than a lot of us had suspected."

-- With Aaron Ricadela