Path: utzoo!attcan!uunet!jarthur!elroy.jpl.nasa.gov!decwrl!shelby!portia!dhinds
From: dhinds@portia.Stanford.EDU (David Hinds)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Replacing an 80386 with an 80486
Message-ID: <9673@portia.Stanford.EDU>
Date: 1 Mar 90 17:56:17 GMT
References: <29108@amdcad.AMD.COM> <1640057@hpspcoi.HP.COM> <9830@sequoia.UUCP>
Sender: David Hinds <dhinds@portia.stanford.edu>
Organization: Stanford University
Lines: 29

In article <9830@sequoia.UUCP>, cb@sequoia.UUCP (Christopher D. Brown) writes:
> ?!?!?!? If you have a 386 why would you switch to a 486 instead of adding
> a 387?
> 
> The only IMPORTANT differences, as I understand, are as follows:
>    1) Intel i$ $pending lot$ of dollar$ trying to make u$ believe
>       that the 486 is my$tically better than 386+387.
>    2) The 386+387 configuration is available and works.
>    
> What am I missing?
> 
    It seems to me that the superiority of the 486 is a bit more than
mystery.  First, it sounds like it would be reasonable to expect a 486
stuck in a 386 board to run about 2X as fast as the 386 at the same
clock speed and with the same support hardware, due to improved pipelining
and the internal cache.  Second, the 486 floating point unit is supposed
to be like an order of magnitude faster than a 387.  If adapting a 486
to a 386 socket is trivial, as it sounds like it might be, the cost of the
upgrade would be little more than the cost of the 486.  Sounds to me like
an easy way to upgrade, no?
    A peripheral advantage of the 486 market is that it will put a lot of
pressure on 386 and 387 prices, since a 386+387 needs to be quite a bit
cheaper than a 486 for Intel to hope to save both markets.  I don't know
what a 486 costs now - as a guess, say $1000 for 25MHz?  If this is cut
in half over the next year, which would not be unreasonable, that would
push similarly clocked 386+387 prices into the basement.

 -David Hinds
  dhinds@popserver.stanford.edu