The biggest headline about the Core 2 Extreme QX9650 is that it is Intel's first desktop processor to use a 45nm production process. The company's previous generation of desktop CPUs were produced using a 65nm process. But why is this change so important, and what does it mean for the processor business?

Die shrink another day

CMOS manufacturing advances trace the history of CPUs as much as the designs of the processors themselves. Each shrink in the size of the microscopic transistors, which make up the CPU, means more can be fitted in the same space, with a number of implications.

At the most basic level, you couldn't even make today's processor designs with the process technologies of just a few years ago - they would be unfeasibly massive. The 386 had just 275,000 transistors. Intel's Core 2 Extreme QX9650 has around 800 million - nearly 3,000 times as many. Using the 386's 1µm production process, the QX9650 would be about a foot square!

Power requirements are another issue. Smaller transistors consume fewer watts to cycle, which again means you can practically have more of them than with a larger process technology.

If you made up enough transistors for a QX9650 with 386s, they would consume around 3000W - yet an entire Core 2 Extreme QX9650 PC, including other components, only requires a little over 200W under full load.

Why smaller is better

Lower power consumption has another handy side effect. If your transistors draw fewer watts, they won't get so hot. So you can run them at a higher frequency without burning them out - or overloading the motherboard power supply circuitry they draw from.

There are other factors to consider, but each new process technology almost always means a higher ceiling on clock frequencies.

The last, but far from least benefit of smaller transistors comes when you keep the basic CPU design the same. In this case, the processor itself becomes smaller - known as a 'die shrink'. Since the fabrication system uses a standard-sized semiconductor wafer - currently 300mm is the largest - you can fit more onto each one.