In what has become scripture for the computer age, Gordon Moore, co-founder of Intel, predicted that the cost of microchip transistors would continue to fall because the number that could be etched into a given surface area of silicon would double every two years or so. Derived from his 1965 paper, “Cramming more components onto integrated circuits”, and subsequent writings, Moore’s law, as his forecast came to be called, turned into a self-fulfilling prophecy. Treating it as a target, chipmakers have, every couple of years, produced a generation of smaller transistors and, therefore, cheaper computing power.

However, it looks as though Moore’s law will not survive 2014. Chipmakers such as IBM, Intel and TSMC, a Taiwanese giant, will probably manage to cut transistor size in half at least a couple more times. The problem, analysts reckon, is that beyond 2014 shrinkages will no longer cut transistors’ cost.

In 2002 a dollar purchased about 2.6m transistors with features as small as 180 nanometres, or millionths of a millimetre. In 2014 transistors with features one-ninth that size will cost just 20m to the dollar. Yet shrinking transistors further will make them more expensive. In 2015 a dollar will buy 19m (see chart). This is because an expensive basket of technologies must be developed for each new generation of smaller transistors (they are already smaller than the wavelength of the light with which they are etched).

Mr Moore himself said at a 2003 chipmakers’ conference that another decade of smaller, cheaper transistors was “probably straightforward”. But now many are surprised as brakes are being “slammed on”, says Linley Gwennap of the Linley Group, a Silicon Valley consultancy.

A future generation of smaller transistors will, no doubt, bring prestige to its maker, says Len Jelinek of IHS, another consultancy forecasting the end of Moore’s law. But neither consumers nor investors will welcome an increase in the cost of raw computing power.

Benjamin Sutherland: freelance correspondent, The Economist