Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!utastro!hgcjr
From: hgcjr@utastro.UUCP (Harold G. Corwin Jr.)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 386SX replacements for 80286 machines
Summary: New 386SX motherboard:  has anybody done this?
Keywords: 386SX motherboard questions.
Message-ID: <4521@utastro.UUCP>
Date: 2 Nov 89 18:14:24 GMT
References: <786@awdprime.UUCP> <1989Nov2.080213.2989@ico.isc.com> <1533@crdos1.crd.ge.COM>
Organization: U. Texas, Astronomy, Austin, TX
Lines: 37

In article <1533@crdos1.crd.ge.COM>, davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes:
>   The easiest way to do this is by replacing the motherboard. You should
> be able to get a new SX motherboard for about $350-400 (I have seen
> dealer prices of $286 if you can qualify). This will NOT give you all of
> the performance of a 386DX, but it will run DOS programs at the speed of
> a 16MHz AT, and you can use 16 bit memory with no penalty. Actually you
> pay the penalty all the time, but it's still fast.
> 
>   It may be cheaper to replace the m.b. than to try to fake in an
> adaptor for an SX or DX chip using the old board.

I've been thinking of doing this myself.  Has anyone on the net actually
put a 386SX motherboard in an AT or a clone?  If so, would you be willing 
to comment on the project?  I am personally interested in the whole thing,
all the way from choosing a board and a dealer, through the actual mechanical
installation, to the moment of truth -- does it work as advertised or not?

Particular questions of mine:  can the 120ns 256Kb RAM on the AT motherboard 
be used successfully on a new board, or should I plan on buying faster RAM?
Similarly, what about my extended/expanded memory board with the same sort
of RAM?  The thought of replacing 2.5MB at today's costs for 80 or 100ns
RAM doesn't thrill me too much.  (I'm not particularly interested in speed, 
but mostly in the 386's memory management skills that are supposed to ease 
the problems of multitasking, working with large programs, data files, etc.)
How about video cards and serial/parallel ports?  Can I use the ones I've got 
now, or will this be an added expense, too? (I'd like to keep my Hercules 
card until I have software that will use VGA.)  I know that I'll need a new 
hard/floppy controller, as well as a 387SX.

All these details may not be of general interest, so e-mail and I'll summarize 
if there is indeed enough interest.  Many thanks!
Harold Corwin
-- 
Harold G. Corwin, Jr.
  UUCP: {backbonesite}!{noao,cs.utexas.edu}!utastro!hgcjr
  Internet: hgcjr@astro.as.utexas.edu           MaBell: 512-471-7463
  Astronomy Dept., RLM 15.308, Univ. of Texas, Austin, TX 78712-1083