When I first started reading Ars Technica, performance of a processor was measured in megahertz, and the major manufacturers were rushing to squeeze as many of them as possible into their latest silicon. Shortly thereafter, however, the energy needs and heat output of these beasts brought that race crashing to a halt . More recently, the number of processing cores rapidly scaled up, but they quickly reached the point of diminishing returns. Now, getting the most processing power for each Watt seems to be the key measure of performance. None of these things happened because the companies making processors ran up against hard physical limits. Rather, computing power ended up being constrained because progress in certain areas—primarily energy efficiency—was slow compared to progress in others, such as feature size. But could we be approaching physical limits in processing power? In this week’s edition of Nature , The University of Michigan’s Igor Markov takes a look at the sorts of limits we might face. Clearing hurdles Markov notes that, based on purely physical limitations, some academics have estimated that Moore’s law had hundreds of years left in it. In contrast, the International Technology Roadmap for Semiconductors (ITRS), a group sponsored by the major semiconductor manufacturing nations, gives it a couple of decades. And the ITRS can be optimistic; it once expected that we would have 10GHz CPUs back in the Core2 days. The reason for this discrepancy is that a lot of hard physical limits never come into play. Read 17 remaining paragraphs | Comments

Read More:
Are processors pushing up against the limits of physics?