NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/sys/intel/2928

Internet Message Format | 1993-01-07 | 1.7 KB

Path: sparky!uunet!mcsun!uknet!comlab.ox.ac.uk!oxuniv!callahan
From: [e-mail]
Newsgroups: comp.sys.intel
Subject: Re: 486dx, 486sx, 386sx
Message-ID: <[e-mail]>
Date: 7 Jan 93 20:37:26 GMT
References: <[e-mail]>
Distribution: comp.sys.intel
Organization: Oxford University VAX 6620
Lines: 27

In article <[e-mail]>, [e-mail] (Lon G. Parisi) writes:
> Hello all,
> I know this question has been perpetuated over and over, but with so many
> responses and opinions, I have to ask. What is the difference between
> the 486sx and 486dx.  I have called Intel directly. The have told be that
> there is no difference in the chip other than the dx has a coprocessor.
> Intel stressed to me that the 486sx WAS a true 486 unlike the 386sx which was
                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^
> a glorified 286 chip.
  ^^^^^^^^^^^^^^^^^^^^
Wow.  Did they really say that?  The 386sx runs 32-bit code and supports
page-based virtual memory; the 286 doesn't.

In fact the instruction set architecture (including the privileged part
used by operating systems) of the 386sx differs only in minor respects
from that of a top-of-the-line 486DX2/66.  Meanwhile it differs dramatically
from that of a 286.  So, IMHO, it makes more sense to describe a 486DX2/66
as a 'glorified 386sx' than it does to say what Intel apparently told you.

Anyway, to answer your question, the difference between a 486SX and a 486DX
is that the DX has a built-in math coprocessor, and the 486SX doesn't.

Michael
---
Michael Callahan
[e-mail]
[e-mail]