Re: How are CPU Speed and Overall CPW Related?

Nathan,

CPW is a slippery topic.  It is a lot more complicated than just
the speed of the processor.  For starters, CPW is always measured
with the maximum memory and disk that is allowed on a specific model.
Your mileage may vary.  Particularly if you don't have the
same resources available to deliver data to where the cpu can
do something with it.

There are many factors that can influence how much work gets
done, which is --theoretically-- what CPW is about.  The number
of disk arms is often a performance limiting factor.  The amount of
cache memory in various places is also crucial... L1 cache, L2 cache,
disk IOP cache, main memory functioning as cache.  And what is
the application?  If you are calculating artillery trajectories,
or three dimensional wire drawings of real objects rotating in
space, then raw CPU speed is a pretty good measure of the work
being done.  In a business application, quite often, raw cpu
is not what you are short of...

This topic deserves more discussion.

Charly Jones
Geezer in Gig Harbor



>From: "Nathan M. Andelin" <nathanma@haaga.com>
>
>I had previously assumed that CPU speed and CPW rating were closely 
>related.
>Apparently I was mistaken.  Midrange Computing recently published charts
>that would suggest otherwise.  For example, the model 170-2160 has a 100 
>Mhz
>Apache processor and a CPW rating of 114, while the model 170-2290 has a 
>200
>Mhz Northstar processor and a CPW rating of only 73.  Can anyone explain
>this?  Is there a governor on the 170-2290 that causes it to handle less
>work than the 170-2160?
>

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