Many vendors use all of the techniques listed above and embed these techniques inside a machine with multiple CPUs. The following is an example of a Micronics M6Me, dual processor motherboard for Pentium 150 to 200 MHz processors.
This is typical of the 1996-1997 products being made available. The average user who surfs the WEB probably doesn't need it; however, a business with a LAN and Internet connections may have a true need for this amount of processing power. Still, those who process programs such as multimedia that is processor intensive may find that a machine with multiple CPUs provide much faster results.
Multiple CPU processors have been around for 30+ years, but not in the Microprocessor world. The need surfaced several years in the past, but blossomed with the advent of operating systems capable of running applications on such a system. MS-DOS, PC-DOS, etc. did not have the capability of running multiple tasks; however, Windows NT Server, Windows NT Workstation, WIN95, etc. made the use of such systems feasible.
Several vendors, among them DEC and Zenith, have products that have up to 4 CPUs. The Zenith Z-Server and DEC AlphaServer line of products do this.
POINT OF CAUTION:
Adding a CPU will not increase the throughput of the PC by 100%. A more reasonable estimate would be an increase of 50-60%. But multiple CPUs help in a multi-tasking, multi-processing environment.