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From: brandis@inf.ethz.ch (Marc Brandis)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Comparing 486 to 386 Systems
Message-ID: <27865@neptune.inf.ethz.ch>
Date: 5 Apr 91 10:27:28 GMT
References: <40409@netnews.upenn.edu> <1991Apr4.062503.1325@agate.berkeley.edu> <1991Apr4.142742.20601@lonex.radc.af.mil> <1991Apr4.204923.29300@agate.berkeley.edu>
Sender: news@neptune.inf.ethz.ch
Reply-To: brandis@inf.ethz.ch (Marc Brandis)
Organization: Departement Informatik, ETH, Zurich
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In article <1991Apr4.204923.29300@agate.berkeley.edu> c60b-1eq@web-1c.berkeley.edu (Noam Mendelson) writes:
>Most people also subscribe to the notion that if the number is higher it's
>necessarily much more powerful, where in fact:
>		(486 - 386) < (286 - 86) << (386 - 286).

Well, I guess you subscribe to a similar notion which is also wrong, like most
performance comparisons that oversimplify. In fact, (386-286) is the smallest
of the differences, not by far the largest as your relation indicates. Give
me any instruction on the 386 except multiplies that are faster than on the 
286. I know you will not find one. Of course, I am comparing apples to apples
and oranges to oranges, namely CPUs running in the same mode at the same clock
frequency.

While it is true that the 486 is not that much faster than the 386 on non-fp
code running 16-bit software, you should see a larger difference running 
32-bit code.


Marc-Michael Brandis
Computer Systems Laboratory, ETH-Zentrum (Swiss Federal Institute of Technology)
CH-8092 Zurich, Switzerland
email: brandis@inf.ethz.ch