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Grex Micros Item 174: Climbing out of the slime of the 386, or bloodlessly upgrading to a 486.
Entered by omni on Wed Oct 29 03:58:03 UTC 1997:

      I have an opportunity to upgrade my computer from the  386SX/16
to a 486. The question is which one.

   I'm going to buy the mother board, 8Megs of memory and some
kind of 486 chip. As I understand it, the 486 comes 3 ways.
The 486sx, the 486dx and the 486dx2-50 which I can get for about $20.
I can also buy (I assume for a little more money) a 486 -166Mhz chip with
tailfins and the chrome headlights ;) 

   I know I want to go higher on the food chain, because eventually I
would like a very large hard drive and as I understand it, a 386 can
only address a 540M hard drive. Would someone please explain the
advantages of the 486, and maybe offer some advice on what chip
to buy.
  As I told a friend tonoght, I don't know a computer chip from a potato 
chip. ;)

Thanks in advance for any help you might offer.

12 responses total.

#1 of 12 by scg on Wed Oct 29 06:41:17 1997:

To put it simply, the advantage of a 486 over a 386 is that the 486 is faster.
Likewise, the advantage of a Pentium over a 486 is that the Pentium is faster.
It's not like the division between a 286 and a 386, where software written
for the 386 often wouldn't run on a 286.  To get to that level, you have to
get up to the Pentium Pro or MMX, but even now there isn't that much much
software that absolutely requires one of those.

The 486 actually comes in four types of CPUs, and many more types of
motherboards.  The types of CPU are SX, DX, DX2, and DX4.  The SX has no math
coprocesser, while the DX and up do.  The DX2 is a DX that runs at twice the
speed of the motherboard (the regular DX runs at the same speed as the
motherboard).  The DX4 runs at three (no, that isn't a typo) times the speed
of the motherboard.  Then, all these CPUs come in a range of clock speeds,
but you're probably used that from your older computers.  Just make sure the
motherboard you get supports the clock speed of the CPU.

Then there's the issue of what motherboard to buy.  Motherboards with older
BIOSs only support < 540 MB hard drives, while newer BIOSs support larger hard
drives.  At the 486 level you will also get a choice of several types of BUS,
since in the 486 motherboard era they hadn't really standardized on what sort
of high speed BUS to use.  ISA was the pre-486 standard, and PCI is the
current standard.  You probably want to look for a PCI motherboard, to make
upgrading to a Pentium later more easy (any of these mother boards with
non-ISA BUSs will still have a few ISA slots).  My 486 has a VLB BUS, and I
think there were also a few other options but it's been long enough that I
don't remember what they were.

#2 of 12 by omni on Wed Oct 29 07:01:16 1997:

  Will the PCI or the VLB still support my cards? (modem, vid card,
controller, etc?) What do these look like? Are they marked? 

  So on the surface, I'll go with the 486-DX2-50.
 
  Is there anything that I should read on this before I buy the board?

#3 of 12 by n8nxf on Wed Oct 29 13:09:27 1997:

The machine I'm on right now has a 486DX50 in it.  I set the clock from
25MHz (CPU runs at 50MHz) to 33MHz (CPU runs at 66MHz) after adding a
heatsink and heasink compound.  It's been about a year of 8hr/day use
w/o a problem.
 
I'd go with a clone motherboard form CCS, etc.

#4 of 12 by scott on Thu Oct 30 01:53:46 1997:

If there are enough ISA slots (the old kind like you are used to) you can run
all your old cards.  VESA bus is an ISA bus with an additional connector
behind it,  PCI is a completely different (smaller, denser) connector, and
EISA (Extended ISA) is a weird thing that is *deeper* than ISA.  I'd recommend
avoiding EISA, since it generally involved a kludgy early config system.

#5 of 12 by omni on Thu Oct 30 06:00:03 1997:

  I only need 4 or 5 slots (Modem, video, controller etc).

 Thanks scott and scg for being so eloquent in your explanations of the
hardware. I now need to wait a bit while some things come together.

I'll probably be buying from a place called Bryan Computers on Jackson Rd,
and the memory from Chip Merchant. 

Has anyone done business with Bryan Computers? I know Chip Merchant is a great
place but I've never heard of Bryan Computers.

#6 of 12 by arthurp on Sun Nov 16 01:53:18 1997:

I have a spare 486 DX 33 chip you can have.

#7 of 12 by omni on Mon Nov 17 19:54:29 1997:

 I can certainly use it. 

 I'll mail you.

#8 of 12 by omni on Mon Nov 17 19:58:45 1997:

  Here's a silly question.

  Would it be possible to remove the 386 chip on my present board and drop
in the 486? Or do I have to have a 486 type motherboard?

#9 of 12 by scg on Mon Nov 17 23:34:53 1997:

Nope.  It has to be a 486 motherboard.

#10 of 12 by omni on Tue Nov 18 00:12:16 1997:

 Thought so. Thanks Steve.

#11 of 12 by wolfg676 on Sat Apr 11 09:59:48 1998:

I've got an AMD 486DX2-66 that I could part with, I'll have to see if I can
find a DX4-100 if you'd want it. I *do* have a TI486/DLC that should fit your
386 board, if that's the way you would want to go (not a real good idea).

#12 of 12 by gibson on Sat Apr 11 23:24:27 1998:

        I'd like to upgrade mp 486sx. If one of your chips would work will you
email me price and which one?

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