Chip magicians at work: patching at 45nm

Let us return to the present, and to Penryn. The first version of this chip was produced in December 2006 in the Oregon development facility Fab D1D, which is almost 500 miles north of Folsom. Some fifty engineers stayed up during the night while the A0 version of the processor was flown to Folsom by one of Intel's private aircraft.

Of course they could have waited until the next morning, but they were just too anxious to find out whether the chip, which by then had already been under development for over two years, actually worked. Besides, they were eager to beat the Merom team, that had managed to boot Windows on the A0 version of the Core 2 Duo in under thirty minutes. That night there was both good news and bad news: Penryn worked, but it took six hours to get Windows to boot properly on it.

After the A0 version, several other steppings were made, for reasons such as fixing bugs, improving the yields and enabling higher clock speeds. The version that will hit the shops on November 12 is called C0 and is the fifth revision of the design.

Penryn up close: 420 million transistors on 107mm²

But how does Intel go about testing these things? Simply starting Windows is obviously not sufficient to find out whether or not everything is functioning properly. An all-nighter running SuperPi? Contrary to what many overclockers believe, this, too, is not enough to be able to state that a chip is stable at a given clock speed. And what if a bug is found in the hardware? Penryn crams almost four million transistors on each square millimeter, so surely it is impossible to figure out where exactly it is that things go wrong. Or is it?