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From: ilan343@violet.berkeley.edu (Geraldo Veiga)
Subject: Re: Difference between 386/33 & 486/25 not counting fp
Message-ID: <1991Apr12.073828.20663@agate.berkeley.edu>
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References: <1163@gistdev.gist.com> <1991Apr9.085749.4568@agate.berkeley.edu> <1164@gistdev.gist.com>
Date: Fri, 12 Apr 1991 07:38:28 GMT
Lines: 40

In article <1164@gistdev.gist.com> flint@gistdev.gist.com (Flint Pellett) writes:
>
>(they publish results of 5 different tests in 4 different OS'es and
>about 4 different price categories.  Performance ratios between 386
>and 486 machines seem to follow the same ratios as the ones below.) 
>
>DOS 386 Systems:	Dhrystone	Price
>Micro Express /33	15,870		$4,998
>Laser Ditigal 386/33	15,750		$4,296
>Arche Legacy 386/33	17,134		$8,665
>Northgate 386/33	17,131		$8,919
>
>AST 486/33		34,192		$4,490 (upgrade board)
>Club American Hawk III	35,923		$6,495
>NCR PC486/MC 33		35,234		$14,995
>
>The Dhrystone numbers drop down to around 12K for the 386 machines
>at 25 MHz and down to 26K for the 486's at 25 MHz.  Unless your
>arithmetic is different than mine, that works out to about
>twice as fast, not 50% faster.

How different can the performance of different brands of 486
motherboard be?

The numbers above look highly inflated compared to what I can get in my
system.  I have a 486/25 with 128K cache, based on the OPTI chipset.

Under DOS, QAPlus rates it at 15172 Dhrystones.  Under ISC Unix,
Drhystone 2.1 (source code from netlib, compiled with gcc)  gives a
reading of ~~ 17000.  This is the best I can get, with all memory
addresses cached.

Can different motherboard designs give such radically improved
performance?  I suppose the more likely explanation is that the
benchmark code is not the same.  The only change I made to the
Dhrystone code was the HZ constant used in the timing routine 
(from 60 to 100).

Can anyone enlighten me on this one?