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From: v126gfl3@ubvms.cc.buffalo.edu
Newsgroups: comp.sys.ibm.pc
Subject: Re: Replacing an 80386 with an 80486
Message-ID: <241.25ec328b@ubvms.cc.buffalo.edu>
Date: 1 Mar 90 01:20:27 GMT
References: <29108@amdcad.AMD.COM> <1640057@hpspcoi.HP.COM> <25E98AD7.9457@maccs.dcss.mcmaster.ca> <9589@portia.Stanford.EDU>
Organization: Academic Computing Services, University at Buffalo
Lines: 32

In article <9589@portia.Stanford.EDU>, dhinds@portia.Stanford.EDU (David Hinds) writes:
> In article <25E98AD7.9457@maccs.dcss.mcmaster.ca>, cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) writes:
>> $For example the numeric coprocessor and a memory cache are include in the
>> $chip. As for upgrading, that depends on whether your 386 was designed
>> $for upgrading. There is a major difference in the motherboard design
>> [...]
>> 
>>    Yup ... the whole motherboard has to be replaced unless it was
>> designed for upgrading, and very few machines are designed for upgrading.
>> -- 
>     It seems like it would not be all that hard to design a teeny daughter
> board that fits into the 80386 socket, and carries an 80486.  Is there a
> real difference in design of the support circuitry, that an 80486 wouldn't
> work in place of an 80386?  From what I understand about the '486, to the
> outside world (i.e., the motherboard), it shouldn't look much different from
> an 80386.  I would guess that the 80486 might have a couple extra control
> lines that might need to be tied off somehow, but it should be able to start
> up off of a standard 80386 BIOS, even.  When '486 prices fall, this seems
> like a potentially inexpensive upgrade - instead of getting a fast 80387,
> for example.
> 
>  - David Hinds
>    dhinds@portia.stanford.edu

I would have to agree.  The design of the 486 compared to the 386 is not unlike
the 386 is to the 286, for which there are many options for upgrades, only the
most radical of which is motherboard replacement.  I would have to beleive the
boys at Intel are gonna be working overtime to get an Inboard/486 out on the
market, once they get the bugs out of the 486, that is.

Alex Cutrone
v126gfl3@ubvms.cc.buffalo.edu