Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!think!snorkelwacker!spdcc!esegue!johnl
From: johnl@esegue.segue.boston.ma.us (John R. Levine)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Replacing an 80386 with an 80486
Message-ID: <1990Mar1.164009.15666@esegue.segue.boston.ma.us>
Date: 1 Mar 90 16:40:09 GMT
References: <29108@amdcad.AMD.COM> <1640057@hpspcoi.HP.COM> <25E98AD7.9457@maccs.dcss.mcmaster.ca> <9589@portia.Stanford.EDU> <241.25ec328b@ubvms.cc.buffalo.edu> <9830@sequoia.UUCP>
Reply-To: johnl@esegue.segue.boston.ma.us (John R. Levine)
Organization: Segue Software, Cambridge MA
Lines: 20

In article <9830@sequoia.UUCP> cb@sequoia.UUCP () writes:
>?!?!?!? If you have a 386 why would you switch to a 486 instead of adding
>a 387?

At a given clock rate, a 486 is at least three times faster than a 386.  While
the 386 takes at least two and more often five or six cycles to execute an
instruction, the 486 runs most of its instructions in one cycle each.  The
speedup for floating point is apparently even greater.  When Intel went from
the 286 to the 386, they added a lot of new function but the clocks per
instruction remained about the same.  The 486, on the other hand, is basically
a performance upgrade with a tiny bit of new function to make it easier to
implement multiprocessor systems.

Then again, given that the 486 is still a member of the bug-of-the-month club,
and that it costs considerably more, I'll wait.  People who care about math
speed should consider getting a Cyrix or IIT math chip.
-- 
John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650
johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl
"Now, we are all jelly doughnuts."