Re: Processor types


Subject: Re: Processor types
From: civileme (civileme@mandrakesoft.com)
Date: Fri Jun 21 2002 - 14:36:08 AKDT


On Friday 21 June 2002 07:49 am, Mike Barsalou wrote:
> Can someone give a first grader explanation of the difference between
> Celeron and Pentium, Duron and whatever is the equivalent AMD processor?
> The Duron processors are definately cheaper like the Celeron's but at what
> cost?
>
> Mike
>
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> To unsubscribe, send email to <aklug-request@aklug.org>
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OK Processors are boxes that do things to stuff. They take in and manipulate
the stuff and send processed stuff back out.

The Pentium III has a lot of logic, and more than one execution unit so it
can be doing more than one instruction at a time (or more than one piece of a
complex instruction) It is clocked at a speed called its frequency, measured
in millions of cycles per second or MegaHertz (MHz), or Billions of cycles
per second or GigaHertz (Ghz) . One instruction may take a few or many clock
cycles, but it is safe to say that modern processors do millions of floating
point artihmetic operations (the kind with decimal points and lots of digits)
every second.

Since the Processor can sometimes run instructions faster than it can get
them from memory, there is hyperfast memory onboard the processor chip, often
much more of it that was on the whole memory of desktop computers just a few
years ago. That memory is called CACHE memory and it is used for copies of
instructions and data fetched from main memory. Many operations with
computers involve many, many repetitions of the same instructions in what is
called a program loop. It is in these loops that cache memory helps a great
deal. Since hyperfast memory is expensive to put on a chip, there are often
two levels of cache, both faster than main memory but with Level 1 cache
faster than level2. If a memory request cannot be met on level 1, then level
2 is searched, and if not there, then main memory...

The Pentium and the Celeron are procesors from Intel corporation. They
differ in what seem to be minor ways.

The Celeron has the same internals and execution units as the P-III
The Celeron has no ability to be placed on a mainboard with other Celerons to
make a multiprocessor computer (the Pentium DOES have that capacity)
The Most recent Celerons can operate with a system bus speed of either 66 or
100MHz (this is the clock that is used to gate data from place to place on
the mainboard, and its speed affects the overall speed of the computer
dramatically). The most recent Pentium IIIs use either 133Mhz or 100MHz.
The Celeron has half or less than half the L2 cache memory of the P-III

 Now the processors from AMD (American MicroDevices) are very similar to the
Intel processors. They both perform the same instructions in essentially the
same ways. Their clock speeds are similar except for the very newest, where
different architectural approaches have been utilized to achieve the same
performance.

The Duron and Athlon have larger L1 caches than the Pentium or the Celeron.
In fact the Duron has a larger L1 cache than its level 2 cache.

The Athlon has the most cache of any of the processors

While the system buses are still 100 for the Duron and 100 or 133MHz for the
Athlon, the Front-side bus, the part that communicates with memory, runs at
200MHz or 266MHz.

So the Duron and the Athlon do outperform their clock equivalents from the
P-III and Celeron world, but there is a price.

The Athlon Thunderbird and the Duron have no thermal overload shutdown as the
Celeron and P-III do. This means that if the motherboard does not have an
overheating shutdown feature, a dead fan means a fried processor.

Athlon T-birds, Athlon XPs (the rough equivalent of the P4) also have
multiprocessor capability, and the new Athlon MP is built expressly for
multiprocesor configurations.

Finally there is the upgrade path.

Not much remains to be done in terms of making processors smaller and faster
with silicon. Memory is at the point where an alpha particle is energetic in
comparison to stored memory charge--in fact this was a problem with come
memory chips where a deramic case had some thalium in it. An alpha particle
from radioactive decay was enough energy to flip a bit, even though alpha
particles can almost always be stopped by a sheet of paper.

So we are reaching some theoretical limits for the materials in use. There
are other schemes, which could pack one of today's biggest into a single
cubic inch, but they require expensive materials and special conditions to
work, (like liquid helium temperatures).

The next move up is likely to be to 64 bit processors. Intel has had its
IA-64 out for a while, but none of the software that runs on a pentium will
run on an IA-64. the instructions are different.

AMD is bringing out the Hammer architecture, first to be packaged in a
processor called the Opteron, also 64 bits. It WILL run the current 32-bit
software though to reach full utilization of its resources, some
reprogramming will be necessary.

Is that enough, Mike?

Civileme
 

Both have about the

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