Path: utzoo!attcan!uunet!clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!watserv1!ria!uwovax!baer
From: baer@uwovax.uwo.ca
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: 386 Sx & 387 maths chip (16 Mhz) or 386/25 and no maths chip ??y
Message-ID: <6499.26a985cd@uwovax.uwo.ca>
Date: 22 Jul 90 14:54:04 GMT
References: <6585.26a7b1cc@vax1.tcd.ie> <90202.224428RFM@psuvm.psu.edu>
Lines: 22

In article <90202.224428RFM@psuvm.psu.edu>, RFM@psuvm.psu.edu writes:
> The August 1990 issue of PC RESOURCE (the LAST issue, **SOB**) has an article
> discussing coprocessors. Sets down the issues. Answers???? - Judgement call...
> If most student apps are text-based, I'd go with SXs. If apps are a lot of
> math programming and engineering CAD/CAM, the DX/25s might be as fast as
> SXs with coprocessors. If the DX/25s have cache memory, they'll probably
> be pretty fast without coprocessors.
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Be careful if the application is truly math-intensive.  On a math-intensive
application with relatively little I/O, I'm finding: a) a 386sx + 387sx
combination at 16mHz. is about 1/2 as fast, perhaps a bit better, than 
a 386dx + 387dx combination at 20 mHz. (no cache) b) the 386sx + 387sx
combination at 16mHz. is about twice as fast (perhaps a bit better) than
a 386dx with cache at 25mHz. but without a math chip, c) the 386dx with
cache without a math chip is a slight bit slower than a 286 + 287 at 10 Mhz.
(287 running at 2/3 clock speed of course).



Douglas Baer, 
University of Western Ontario, London, Canada N6A 5C2
Internet: BAER@UWO.CA    Bitnet: BAER@UWOVAX