Sorting the Fast from the Merely Good

Once each chip is tested to see if it's functional, it'll often be tested again to see exactly how fast it is. Natural (although unwelcome) variations in manufacturing will make some chips work slightly faster than others. If the difference is significant (say, 20 percent faster) and if the numbers of these overachieving chips are also significant (about 20 percent or more) then it's probably worthwhile to sell them at a premium price. For highly profitable microprocessor chips for PCs and other computers, this extra financial gravy can be more than $100 per chip.

Other times, it's not worth the trouble to sort the chips by speed. If a good chip sells for only $1.25, a fast one is unlikely to command a premium of much more than 25 cents. For that amount, it's more cost-effective to skip the testing and sell all the parts at the same price. This means some enterprising customers or technicians might be able to discover a few chips in their monthly shipment that are faster than advertised, but that's for them to discover.

Even when faster than average chips do carry a price premium, chip companies will intentionally avoid selling them as such for marketing reasons. Early in a chip's product life, there might be relatively few that make the faster speed cut. Later on, as the manufacturing process matures and the yield improves, there might actually be too many faster parts. The chip maker can arbitrarily limit the number of such parts to, say, 15 percent of the total product offering to maintain the aura of exclusivity surrounding the higher priced part. Technically astute PC hobbyists call this “overclocking.” They will test their computer's chips at home to see what the upper limit of performance is, fine-tuning their PC to extract the maximum possible performance from each chip. Half of the appeal is appearing to cheat the chip maker out of a few extra dollars.