eWEEK at 30: Multicore CPUs Keep Chip Makers in Step With Moore's Law

eWEEK 30: Power and heat issues forced chip makers in the early 2000s to move from single to multiple cores to enable CPU design to keep pace with Moore's Law.

At the Intel Developer Forum in 2001, Paul Otellini stood on stage and showed off a Pentium 4 desktop PC chip running at 3.5GHz. At the time, Intel's fastest chip ran at 2GHz, but the company's plans called for a rapid increase in the frequency of its processors.

"Yesterday, we showed a 2GHz processor," said Otellini, who at the time was an executive vice president and general manager of the Intel Architecture Group and who later became the company's CEO. "Today, we showed a 3.5GHz processor. A 4GHz processor is on the horizon. We're convinced that we can scale the Pentium 4 to 10GHz."

The plan at the time was to crank up the frequency of the chips as the company grew the number of transistors in the processors. In 2000, Intel's fastest Pentium 4—at 1.5GHz—contained 42 million transistors. By 2005, the projections called for chips holding 400 million transistors and running at speeds approaching 10GHz.

At the time, ramping up the speed of the processor was the chief way of increasing its performance. There were other tweaks here and there, such as playing with the cache or tweaking the instructions, but the primary way was through its frequency.

However, even while Otellini and others at Intel boasted about how processor frequencies would continue to increase rapidly over the following years, officials with Intel and other chip makers also were beginning to talk about the problems that arise at such speed, in particular heat generation and power consumption.

That same year, Pat Gelsinger—at the time, the chief architect for Intel's processors and now CEO of VMware—noted that should chip designs continue on that path, they would become as hot as nuclear reactors by the end of the decade and as hot as the sun's surface by 2015. As far as chip development and design went, it was "no longer business as usual," he said, speaking at the IEEE's International Solid State Circuits conference that year. "No one wants to carry a nuclear reactor in their laptop onto a plane."

During his talk, Gelsinger raised a couple of options that already were beginning to be used by two other chip makers, IBM and Sun Microsystems: running multiple instruction threads on the chip and assembling multiple processing cores on a single chip.

If Intel, Advanced Micro Devices and others were to keep up with customer demands for ever more power and the cadence of Moore's Law, it was clear that something needed to be done beyond pushing the frequency.

"There was a constant demand from end users for more performance," Nathan Brookwood, principal analyst for Insight 64, told eWEEK. "To keep performance going on its growth curve, you had to go multicore."