Speed, Power, and Heat
Two charts published by tech site Tom's Hardware show that processor performance appears stuck below 4 GHz, while energy consumption has plateaued at 130W. Is the solution to more performance merely cranking up the juice? It's not that easy.
Tom's Hardware, in a comprehensive review of CPU performance, explains, "The biggest problem that the chipmakers face now is that heat dissipation increases with rising frequencies. So far, neither [AMD or Intel] has been able to find a satisfactory solution. Instead, they have taken advantage of the advances in miniaturization of the processors themselves, and begun incorporating two physical cores onto one die. This technique helps spread the heat more evenly across the processors' surface . . . For now, however, the 4 GHz barrier seems to remain an insurmountable obstacle - at least while trying to retain justifiable heat dissipation levels. After all, a thermal dissipation loss of 130 W requires an expensive and extravagant cooling system that isn't easily realized in the mass market." Tom's goes on to advocate a "performance per watt" benchmark for processors.
One more reminder that the energy/carbon cost of increased performance is not only in the increased cost of powering the machines, but also in the increase cost of dealing with the waste heat.
Computer scientist Peter Kooge explains why energy and heat are now the barriers to be overcome in order to achieve the next big leap in supercomputing. His version of a new benchmark is "performance per joule". To listen, go to "Peter Kooge Talks" in the December 2008 section of IEEE Spectrum Podcasts.
'Probabilistic' logic is said to allow a computer chip to run faster, use less power. Rice University announced, "In the first real-world test of a revolutionary type of computing that thrives on random errors, scientists have created a microchip that uses 30 times less electricity while running seven times faster than today's best technology. The U.S.-Singapore team developing the technology, dubbed PCMOS [pronounced "pee-cee-moss"], revealed the results here today at the International Solid-State Circuits Conference (ISSCC), the world's premier forum for engineers working at the cutting edge of integrated-circuit design."