Multiprocessing: Functions and Features

A PC with two or more processors does not offer advantages by itself. To use the unified processing power operating system and applications need to play along. sheds light on the special features of multiprocessing.

When it comes to high-end models of CPUs, processor manufacturers charge heavily for each megahertz delivered. For example, the move from a Pentium 4 with 1.4 GHz to 1.7 GHz to gain 20 per cent more clock speed rings in an additional charge of 80 per cent (as of May 2001). A Xeon equipped with 2 MByte cache and 30 per cent more clock speed is priced almost 90 per cent higher. Apparently, this unfavorable relationship between price and performance can be avoided by using a multiple processor system. A suggested performance increase of 100 per cent will cost about the double amount. Necessary chipsets and mainboards for multiprocessing are more complex and are produced in small number. This results in significantly higher system prices.

If a multiprocessor system is considered, it is important to know that many applications are not accelerated in such an environment and in some cases even can slow down. This article explains dependencies of performance gains and clarifies who will profit from the use of a multiprocessor system.