From the beginning, Intel designed the Coppermine line of processors to have plenty of headroom. Apparently they did a good job of it, with speeds ranging from 500MHz now to 1GHz, all without a significant change in design. But this gets into what appears to be Intel's overall IA-32 design philosophy of taking what works and building upon it. The Pentium III 1GHz's core is the same as any other Intel CPU based upon the sturdy P6. In much the same way as a good French Burgundy, the P6 core has not only aged, but it's matured well into a 'vintage.'

One method Intel uses with the Coppermine to run it at speeds of up to 1GHz is through the use of what they call a "notched poly profile." Take a normal .13 micron long gate, cut tiny notches in it to decrease its width to .10 micron, and you get a .13 micron gate that works as fast as a .10 micron gate. So through the use of these notches, Intel can manufacture faster processors on an older process.

Previously, it has been thought that Intel would have to switch from aluminum based interconnects to copper based ones in order to reach 1GHz. However, Intel managed to pull a rabbit out of their hat and extend the life of aluminum interconnects by making necessary space allowances for problematic aluminum interconnects. Call it a hack or call it clever engineering, but the Pentium III 1GHz uses aluminum interconnects with no apparent effect on CPU speed. According to Intel, the speed of the Coppermine design is purely transistor limited.