Re: How are CPU Speed and Overall CPW Related?

["Neil Palmer" <neilp@xxxxxxxxxxx>]

IBM didn't come up with the name Magic Box from nowhere.  Rochester has 
had it's box of magic tricks for restricting performance on the cheaper 
models for many years.  It's no co-incidence that a 170-2290 has 1/3 the 
CPW rating of a 2292. 
A 270-2248 & 2250 are both 400Mhz Pulsar processors, yet one has a CPW of 
150 and the other 270.   Besides, you are trying to compare performance 
between an Apache and Northstar processor - so there are other things to 
consider, like cache for example, in the two different designs.
It's no different than a car manufacturer selling several versions of 
basically the same engine, with the more expensive versions tuned for 
higher performance.

...Neil





"Nathan M. Andelin" <nathanma@haaga.com>
Sent by: owner-midrange-l@midrange.com
2001/04/30 13:17
Please respond to MIDRANGE-L

 
        To:     <MIDRANGE-L@midrange.com>
        cc: 
        Subject:        Re: How are CPU Speed and Overall CPW Related?


Several week ago, List participants shared performance statistics 
pertaining
to string handling in RPG, Java, and MI.  Ken Slaugh shared an RPG code
sample that did some simple string manipulation within a tight loop.  So 
the
work was entirely CPU bound.  I ran a fully optimized copy of his program 
on
my machine.  The elapsed CPU time on his machine to run the program was
1260000 *MS.  The elapsed time on my machine was 2100000 *MS.  His machine
had a CPW rating of 114.  My machine had a CPW rating of 73.  So there
appeared to be a close correlation between machine CPW and program 
execution
speed.  Now I have learned that his machine has a 100 Mhz Apache 
processor,
and my machine has a 200 Mhz Northstar processor.

Why did it take my machine more CPU time to run the program?  It was the
only thing running at the time (other than normal Jobs, holding in a Wait
state), so it was not affected by other Jobs.

Thanks,

Nathan.


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