Why two processors are better than one
Increasing computer efficiency drives people to do many things, and one of
the most common is doubling-up, or tripling-up, or even quadrupling-up, on
processors. The processor works at high speeds to perform the basic tasks that
are central to using your computer. It processes your instructions to do things
like open programs, copy files, and make all those blinky lights move around on
your monitor.
Processors rely on two unique sources of memory in order to hang onto certain
pieces of data while processing others. The first level of memory is the
processor's register. The register is to the processor what the RAM is to the
computer as a whole; it stores information that is currently being worked with.
A secondary source of storage space is known as the cache. There are generally
two caches that processors can draw from, and while neither of them is as fast
at retrieving data as the register, they are both substantially speedier than
the computer's RAM or hard drive (even deeper memory-sources that the processor
can tap).
If your processor is responsible for so many of your computer's functions,
wouldn't it make sense to install more than one of them? Well, yes and no. More
than one processor, or a multiprocessor, if you will, can up your speed, but it
also ups your need for auxilliary hardware. This, in turn, ups your cost. So
whether you should consider multiprocessing really depends on how you use your
PC.
Most people who use their PC as a PC -- as a personal computer, with the
stress on the personal -- have no need to multiprocess. Multiprocessing is most
commonly used in environments where unwieldy databases are being employed, or
where complex graphics are being developed, or where high-traffic internet
servers are needed. However, it can't hurt to go through some of the basics of
multiprocessing just to get a handle on the multiplicity of your computing
options.
For a start, there is more than one way to go about multiprocessing.
Symmetric multiprocessing (SMP) involves two or more processors attached to the
same RAM and hard drive. In SMP, the same processing task gets divided equally
among different processors. Another method is called asymmetric multiprocessing
(AMP), and it also shares RAM and system resources among more than one
processor. The difference here has to do with the tasks the different processors
effect. In AMP, one processor handles applications while the other runs system
tasks. Massively parallel processing (MPP) does away with shared resources. In
MPP systems, each processor uses its own RAM and system bus. This means neither
processor has to wait to access the system bus or the RAM, allowing all
processors to optimize their performance speeds.