Configurable Computing; June 1997; Scientific American Magazine; by Villasenor, Mangione-Smith; 6 Page(s)

Computer designers face a constant struggle to find the right balance between speed and generality. They can build versatile chips that perform many different functions relatively slowly, or they can devise application-specific chips that do only a limited set of tasks but do them much more quickly. Microprocessors (such as the Intel Pentium or Motorola PowerPC chips commonly found in personal computers) are general purpose: programming instructions encoded in binary format can lead a microprocessor through virtually any logical or mathematical operation a programmer can conceive. The Intel Pentium, for example, was never designed specifically to execute either Microsoft Word or the computer game DOOM, but it can run both.

In contrast, custom hardware circuits, often known as application-specific integrated circuits (ASICs), provide precisely the functionality needed for a specific task. By carefully tuning each ASIC to a given job, the computer designer can produce a smaller, cheaper, faster chip that consumes less power than a programmable processor. A custom graphics chip for a PC, for instance, can draw lines or paint pictures on the screen 10 or 100 times as quickly as a general-purpose central processing unit can.