Processing Power and Speed
The human brain - We can only estimate the processing power of
the average human brain as there is no way to measure it quantitatively as of
yet. If the theory of taking nerve volume to be proportional to processing
power is true we then, may have a correct estimate of the human brain's
processing power.
It is fortunate that we understand the neural assemblies
is the retina of the vertebrate eye quite well (structurally and
functionally) because it helps to give us a idea of the human brain's
capability.
The retina is a nerve tissue in the back of the eyeball
which detects lights and sends images to the brain. A human retina has a size
of about a centimeter square is half a millimeter thick and is made up of 100
million neurons. Scientists say that the retina sends to the brain,
particular patches of images indicating light intensity differences which are
transported via the optic nerve, a million-fiber cable which reaches
deep into the brain.
Overall, the retina seems to process about ten
one-million-point images per second.
Because the 1,500 cubic centimeter human brain is about
100,000 times as large as the retina, by simple calculation, we can estimate the
processing power of a average brain to be about 100 million MIPS (Million
computer Instructions Per Second ). In case you're wondering how much speed
that is, let us give you an idea.
1999's fastest PC processor chip on the market was a 700
MHz pentium that did 4200 MIPS. By simple calculation, we can see that we would
need at least 24,000 of these processors in a system to match up to the total
speed of the brain !! (Which means the brain is like a 168,0000 MHz Pentium
computer). But even so, other factors like memory and the complexity of the
system needed to handle so many processors will not be a simple task. Because
of these factors, the figures we so childishly calculated will most probably be
a very serious underestimate.
The computer - The
most powerful experimental super computers in 1998, composed of thousands or
tens of thousands of the fastest microprocessors and costing tens of millions
of dollars, can do a few million MIPS. These systems were used mainly to
stimulate physical events for high-value scientific calculations.
Here, we have a chart of processor speeds for the past
few years.
|
Year
|
Clock Speed (MHz)
|
Instruction Rate (MIPS)
|
|
1992
|
200
|
200 (400)
|
|
1993.5
|
300
|
300 (600)
|
|
1995
|
400
|
800 (1600)
|
|
1996.5
|
500
|
1000 (2000)
|
|
1998
|
600
|
2400 (3600)
|
|
1999.5
|
700
|
2800 (4200)
|
|
2000
|
1000
|
?
|
From the chart above, we can observe some break through s
in microprocessor speeds. The current techniques used by research labs should
be able to continue such improvements for about a decade. By then maybe
prototype multiprocessor chips finally reaching MIPS matching that of the brain
will be cheap enough to develop.
Improvements of computer speeds however have some
limitations. The more memory it has, the slower it is because it takes longer
to run through its memory once. Computers with less memory hence have more
MIPS, but are confined to less space to run big programs. The latest, greatest
super computers can do a trillion calculations per second and can have a
trillion bytes of memory. As computer memory and processors improve, the
Megabyte/MIPS ratio is a big factor to consider. So far, this ratio has
remained constant throughout the history of computers.
So who has more processing power ?
By estimation, the brain has about 100
million MIPS worth of processing power while recent super-computers only has a
few million MIPS worth in processor speed. That said, the brain is still the
winner in the race. Because of the cost, enthusiasm and efforts still required,
computer technology has still some length to go before it will match the human
brain's processing power.
