Heat is becoming one of the most critical issues in computer and semiconductor design, according to Intel CTO Pat Gelsinger, who will discuss the issue in a keynote Monday at the International Solid-State Circuits Conference. The five-day convention in San Francisco is dedicated to semiconductor research.
Ten years from now, microprocessors will run at 10GHz to 30GHz and be capable of processing 1 trillion operations per second--about the same number of calculations that the world's fastest supercomputer can perform now.
Unfortunately, Gelsinger said, if nothing changes these chips will produce as much heat, for their proportional size, as a nuclear reactor. Not only that, but with more than a billion transistors, they will start to look like rodeo belt buckles. From an engineering standpoint, as well as a financial one, that is untenable.
"We believe power and power density becomes a fundamental issue," he said. "We have a huge problem to cool these devices, given normal cooling technologies...We need to put much more emphasis on transistor design."
Gelsinger's speech will outline some of the methods Intel is experimenting with to reduce power consumption. One technique, for example, focuses on creating more special-purpose sub-sections inside the larger microprocessor. These sections would perform only certain tasks and be activated only when necessary.
Meanwhile, IBM will discuss a 1.1GHz Power4 server processor that contains two processor cores while Sun will present a paper on a dual processor chip from its MAJC family for devices. Compaq will also discuss a 1.2GHz Alpha chip.
Intel is also looking at integrating multiple microprocessors onto a single piece of silicon, a technique IBM is already working on for its server chips. Power consumption goes down, essentially, because electrons don't have to travel as far. Intel is also tinkering with insulating techniques that prevent transistors from "leaking" electricity.
In addition, software will be tweaked to reduce redundant requests to the processor.
Meta Group says shrinking a chip's features reduces the problem of heat, but architectural improvements, like Intel's Mobile Voltage Positioning, are the true key to future improvements.
Increasing transistor count has served as the bedrock of computing advances over the past 30 years. However, it has also meant an increase in the amount of power required to run a processor, which in turn leads to heat.
In addition, microprocessors are growing about 14 percent in size every two years.
"We see a landscape where, for the next 10 years, we can keep Moore's Law running," Gelsinger said. But unless insulating techniques are created and adopted, the pace of development will likely slow.
The emphasis on heat, he added, is relatively new.
"We haven't limited our designs by power in the past. We have limited them by cost and manufacturability," Gelsinger said. "Some of the things we did in the past are no longer applicable."
Heat and power consumption emerged as an issue in the computer world in January 2000 when Transmeta introduced a line of notebook chips that the company asserted consume less energy than competing products from Intel or Advanced Micro Devices.
The appeal of Transmeta's Crusoe processors initially came from the fact that the chips would let notebooks run longer on a single battery charge. However, a group of start-ups is adopting the chips for servers that should hit the market in the first half of the year.
With ASPs (application service providers) packing hundreds of servers into small rooms, heat, not to mention the cost of electricity, has become a huge problem. Servers, for instance, have been known to melt after air-conditioning failures.
"Heat is the primary killer of electronic hardware," said Chris Hipp, chief technology officer at RLX Technologies. "Servers are getting more dense and the processors are getting hotter and hotter and consuming more power."
Although Transmeta has come to prominence through the heat issue, Intel executives said they have been incorporating heat-management technologies into their chips for some time, said Glen Hinton, an Intel research fellow. Some of these techniques were incorporated into the Pentium 4.
With the Pentium 4, he said, "We've been able to reduce power consumption compared to what historical trends have been." The chip also has an automatic switch-off feature that prevents meltdowns.
"On the Pentium 4, power was an important factor but not the most important factor," Hinton said. In the future, "it will be as important or more important than performance...It will change the way we design the microarchitecture."