Microprocessors since 1989

In 1989 a forward-looking paper attempted to determine the characteristics of microprocessors in the year 2000. Called “Microprocessors circa 2000”, the paper hypothesized that a high-performance microprocessor in the year 2000 would have an area of 1 square inch (645 sq mm), contain 50 million transistors, and run at above 250 MHz [1]. The overall performance of the microprocessor was estimated at 2000 million instructions per second (MIPS), achieved by the employment of two or three cores, each with a performance of 750 MIPS. Forward-looking papers often have somewhat fanciful conceits of future developments, illustrating the witticism that predictions tend to be difficult if they involve the future. This prediction, however, was based on many years of microprocessor development, leading to a broadly accurate prediction of things to come. The International Solid State Circuit Conference (ISSCC), held in early 2000, presented a number of microprocessors whose transistor counts and area were within 2× of the prediction. Since much of the area of a microprocessor is composed of on-chip memory, the prediction for transistor count was achieved soon afterwards. The prediction of 2000 MIPS for the maximum performance of the system also proved to be accurate. The interesting discrepancy was in the way that the performance of the microprocessor was achieved. Instead of employing a number of processors operating at 250 MHz, most high end microprocessors were single core designs running at or above 1 GHz.