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From: dlow@pollux.HP.COM (Danny Low)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Need help deciding 386SX vs 386DX
Message-ID: <5870018@pollux.HP.COM>
Date: 9 Jan 91 17:33:42 GMT
References: <1991Jan7.030733.23787@dhw68k.cts.com>
Organization: HP Lovecraft Division
Lines: 29

>(Dave Egan) 
>I am moving from an Amiga to the IBM world.  I would definately prefer to
>go to a 386Dx (25mhz or more) but the $$$ get to be prohibitive.  I have
>been reading several articles that make give me the impression that software
>that takes full use of the 386DX just isn't there yet, that most software is
>still in the '286 capability range (not using the protected mode).  It appears
>that most compilers/linkers cannot handle this mode, that you must get a DOS
>extender from Phar Lap or Watcom.

There are more and more software coming out that support the 386 specifically.
Mathematica exist only in a 386 version. It will not run on a 286.
Windows and several C compilers support the 386 protected mode. The biggest
difference between the 286 and 386 is the additional memory management
instructions in the 386. There are many programs out there that support this
extension (e.g. QEMM and 386Max). You will find the flexibility this
memory management capbility gives you to be enormously useful.

A cheap way to get a 386 is a 386SX. The only difference between the SX and
DX is the SX has a 16 bit I/O bus while the DX has a 32 bit I/O bus. However
most PCs use the ISA I/O bus which is only 16 bits. So most DX systems
do I/O no faster than an SX system. I know someone whose SX runs certain
applications faster than her DX system. Your system runs as fast as the
slowest bottleneck. For many applications the slowest bottleneck is I/O. 
So an SX with a faster hard disk can run faster than a DX in many cases.

			   Danny Low
    "Question Authority and the Authorities will question You"
	   Valley of Hearts Delight, Silicon Valley
	     HP CPCD   dlow@pollux.svale.hp.com