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From: ddt@ccwf.cc.utexas.edu (David Taylor)
Newsgroups: comp.sys.super
Subject: Re: Cray vs. PC Benchmark
Message-ID: <38230@ut-emx.uucp>
Date: 14 Oct 90 02:57:57 GMT
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Reply-To: ddt@ccwf.cc.utexas.edu (David Taylor)
Organization: The University of Texas at Austin
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In article <161512.23931@timbuk.cray.com> ds@juniper09.cray.com (David Sielaff) writes:
>In article <1990Oct9.192119.4453@murdoch.acc.Virginia.EDU> clc5q@shamash.cs.Virginia.EDU (Clark L. Coleman) writes:

>>I realize that Dhrystones are not meaningful for supercomputer applications,
>>but I thought that the scalar integer MIPS of a Cray would still exceed a
>>PC.

Clark, when you compare PC's to Cray's, you compare VW Bug's to Ferrari's.
Sure, Ferrari's may not get the best mileage, but there are NO substitutes.
You can shop for 386 clones.  There are no Cray clones.

If you're interested in running the Dhrystone benchmark on a Cray X/MP, you're
wasting extremely valuable clock cycles.  There ought to be a law against that.
Try comparing the Perfect Club benchmarks on a PC to a Cray.  I think you'll
find the Cray orders of magnitude faster.  Pay no heed to these canabis-smoking
"PC's-the-speed-of-Cray's" marketers.  Pipe dreamers, the lot of 'em.

>Plus the fact that the /4 part of the machine
>type means that the machine has four CPU's, which is meaningless for this
>benchmark.  All of the timings are for one processor.
  [... stuff ...]
>And finally, Cray's are designed
>for floating point, not integer arithmetic, so a lot of extra conversions
>from integer format to floating point format (and back) will need to be
>done.

Amen!  Would you go muddin' (Texas term meaning driving pointlessly for hours
in a muddy field) in a Ferrari, or would you use it as a high society status
symbol/recreational racing vehicle?

>If you've stayed with me for this long, what it comes down to is this:
>benchmarks, like statistics, say exactly what you want them to.  They are
>not lying.  They're just not telling the whole truth.

Understatement of the year.  SPEC is the closest that comes to the
"whole truth", and even it is pretty far from the mark (bad pun).

>Dave Sielaff
>Cray Research, Inc.

Listen to this man.  He may not be marketing (virtue or vice?), but he is
enlightened.. ;)

	=-ddt->