Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!thyme!kaleb
From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley	)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: 386 vs 386SX
Message-ID: <1990Dec10.161538.16651@thyme.jpl.nasa.gov>
Date: 10 Dec 90 16:15:38 GMT
References: <34117@netnews.upenn.edu> <1990Dec5.211220.13194@msuinfo.cl.msu.edu> <1990Dec10.024523.21545@xrtll.uucp>
Distribution: comp.sys.ibm.pc.misc
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 25

In article <1990Dec10.024523.21545@xrtll.uucp> silver@xrtll.UUCP (Hi Ho Silver) writes:
>In article <1990Dec5.211220.13194@msuinfo.cl.msu.edu> draper@buster.cps.msu.edu (Patrick J Draper) writes:
>$In my experience, running MS-DOS an SX is equally fast as a full 386. I
>$think that is because MS-DOS is a 16-bit system, and runs in 16 bit real
>$mode of 386's. Therefore there is no speed advantage from the 32 bit
>$bus. I may be wrong, and I'm sure someone will correct me if I am.
>
>   You're just a little off.  The 386DX does its instruction fetches
>32 bits at a time, whereas the 386SX (obviously) can't fetch more than
>16 bits at a time.  This gives the DX somewhat higher performance for
>the same clock rate on 16-bit software.
>

For what it's worth, I get the following Dhrystone's:
(Yeah, I know Dhrystone isn't the do all benchmark; anyone got the
source to Bytes' PC benchmarks?)

16mhz 386SX       20mhz 386DX       25mhz 486       Sun 4/330
5000              8000              28000           24000

-- 
Kaleb Keithley                      Jet Propulsion Labs
kaleb@thyme.jpl.nasa.gov

You can please all of the people some of the time,