Hi there anywise! What a good question, and not one that either
company is interested in you finding the answer to.
I'd like quickly to point out that you probably mean gigahertz, rather
than megahertz (ghz, rather than mhz). One gigahertz is equal to 1000
megahertz. This measurement is called "clock speed".
The key thing to note here, is that measuring chips in megahertz is a
faulty metric - it doesn't tell you very much about how well they
really work. A chip running at 3.06 gigahertz may actually perform far
slower than a chip running at 1ghz.
The hertz rating means how many times the processor's internal clock
"ticks" per second. These ticks are called clock cycles.
* The Intel chip ticks three billion sixty million times per second.
* The G4 Mac chip ticks one billion times per second.
A processor is just a huge amount of transistors which can perform a
certain set of instructions (things like "ADD x to y", or "JUMP to
instruction 104"). These instructions all take a certain amount of
clock cycles to perform. A typical desktop processor will have dozens
or even hundreds of instructions, for different purposes.
Say, for example, that the ADD instruction took 12 clock cycles on the
Intel, but only 3 clock cycles on the G4. That would mean that in one
second:
* The Intel could perform about 255 million ADD instructions.
* The G4 could perform about 333 million ADD instructions.
So despite the fact that the G4 has a slower clock speed than the
Intel, in this example it actually outperforms the Intel.
Note that the above is just a made-up example (I don't have the exact
data on the ADD instruction), and in the real world, processors use
many different instructions in differing amounts. The main factor that
tends to dictate price, though, is performance - and in the real
world, the processors inside the Macintosh stand up well in comparison
to Intels.
This way of measuring things is referred to as "Instructions Per
Clock" or "Instructions Per Cycle", and in combination with the
clockspeed, provides a far better way of measuring a processor's
abilities.
So in summary, the reason that the price is similar, is that the
performance is similar. This performance similarity is due to the fact
that the G4, despite a lower clockspeed, accomplishes more
instructions per cycle than the Intel.
It's difficult to find data on these chips, because the manufacturers
would prefer to advertise them on image rather than performance. I did
find one extremely in depth article for you to read, but I must warn
you that a degree in Computer Science would be useful if you wish to
comprehend everything on the page!
See here for more: http://www.arstechnica.com/cpu/01q2/p4andg4e/p4andg4e-1.html
You may also be interested in a presentation by Jon Rubinstein of
Apple, entitled "The Megahertz Myth". Accompanying this presentation,
is a graph comparing Apple and Intel chips when using the program
"Adobe Photoshop".
http://www.apple.com/g4/myth/
I hope this helps you. If anything's unclear, then please feel free to
request clarification before rating this answer!
Thanks,
--seizer-ga
Search strategy:
p4 "instructions per cycle"
p4 vs g4 |
