[comp.sys.ibm.pc.hardware] Which motherboard? & Power supply?

mason@robots.ox.ac.uk (Ian Mason) (01/31/91)

I am posting this for someone, however he does read the
comp.sys.ibm.pc.hardware newsgroup.

----------------forwarded message-----------------

I am thinking of upgrading a XT motherboard to either a 20MHz-286 or
16MHz-386sx. The questions are:

1) Are there any particular make of motherboard that I should avoid?
Are there any particular chipsets (e.g. TI, UMC, C&T, DTK) that I
should avoid? Any praises as well? [Addresses & tel. nos. of suppliers
would be most helpful.]

2) Power consumption: how much can a 150 or 200W power supply handle? 

Thanks in advance --- Delman.

------------------------------------------------------------------------------
   Delman Lee
   Dept. of Engineering Science,
   Oxford University,
   Parks Road,                   Internet & BITNET: delman@sun.eng.ox.ac.uk
   Oxford, OX1 3PJ, U.K..                    JANET: delman@uk.ac.ox.eng.sun
------------------------------------------------------------------------------

hollen@megatek.UUCP (Dion Hollenbeck) (02/02/91)

In article <1173@culhua.prg.ox.ac.uk> mason@robots.ox.ac.uk (Ian Mason) writes:
> 
> I am posting this for someone, however he does read the
> comp.sys.ibm.pc.hardware newsgroup.
> 
> ----------------forwarded message-----------------
> 
> I am thinking of upgrading a XT motherboard to either a 20MHz-286 or
> 16MHz-386sx. The questions are:
> 
> 2) Power consumption: how much can a 150 or 200W power supply handle? 
> 

The question that you did not ask, but should have is:

3)  Are there are any requirements on a power supply dictated by
	a 286 motherboard?

The answer is YES.  It must be an AT power supply, not an XT.
The wattage is irrelevant, that is merely dictated by the amount
of power sucked up by the chips on the board and the add-on cards.
An AT motherboard generally takes less that an XT since it is mostly
CMOS stuff, but AT users tend to put in more cards and therefore
you GENERALLY need more power.

The CRICTICAL factor in a power supply for an AT is filtering.
An XT power supply does not have enough and most likely will send
out very dirty, spiky power on power-up, enough to destroy the
contents of the CMOS RAM more than occasionally.  Sometimes, however,
youe get  an XT power supply that does not do this.  Do yourself
a favor and make sure any power supply you get, regardless ow
wattage, is certified for an AT
--
-----
	Dion Hollenbeck             (619) 455-5590 x2814
	Megatek Corporation, 9645 Scranton Road, San Diego, CA  92121
        uunet!megatek!hollen       or  hollen@megatek.uucp

thoger@solan.unit.no (Terje Th|gersen) (02/02/91)

In article <1173@culhua.prg.ox.ac.uk> mason@robots.ox.ac.uk (Ian Mason) writes:

   I am posting this for someone, however he does read the
   comp.sys.ibm.pc.hardware newsgroup.

   ----------------forwarded message-----------------

   I am thinking of upgrading a XT motherboard to either a 20MHz-286 or
   16MHz-386sx. The questions are:

   1) Are there any particular make of motherboard that I should avoid?
   Are there any particular chipsets (e.g. TI, UMC, C&T, DTK) that I
   should avoid? Any praises as well? [Addresses & tel. nos. of suppliers
   would be most helpful.]

   2) Power consumption: how much can a 150 or 200W power supply handle? 

   Thanks in advance --- Delman.

Re power supplies, I used to run 2 85MB SCSI disks, 3 floppies and 6,5 MB
RAM  (in 256-kilobit DIPs, that's 234 chips..) off a 115 watt PS. Worked like
a charm for over a year. The machine was an oldish '286.

  -Terje
--
____________________________________________________________________________
thoger@solan.unit.no       |                 Institute of Physical Chemistry
THOGER AT NORUNIT.BITNET   | Div. of Computer Assisted Instrumental Analysis
                           |               Norwegian Institute of Technology

wilker@gauss.math.purdue.edu (Clarence Wilkerson) (02/02/91)

One might ask if the costs of upgrading to a 20mhz 286 or
16mhz 386 are worth  if only DOS applications are to be 
used. 12 mhz 286 motherboards are in the $100-150
range, while the fast 286 or the 386sx are $300 and up.
In the case of the the 286 you're just getting an increase in
speed of less than 100%.
Clarence wilkerson

davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (02/04/91)

In article <1173@culhua.prg.ox.ac.uk> mason@robots.ox.ac.uk (Ian Mason) writes:

| I am thinking of upgrading a XT motherboard to either a 20MHz-286 or
| 16MHz-386sx. The questions are:

  Start by dropping the 286 idea. There are enough programs, even common
ones like PKZIP, which use the 386 if they find it, and run much faster
for it. People will tell you that a 286 at the same clock will run the
same program as fast, and while true, the problem is that the 386
version will run up to twice as fast and won't run on the 286 at all.
That also goes for neat memory managers like QEMM, etc.

  An SX isn't much faster for most things, but it is a lot more likely
to be useful in 2-3 years.

| 1) Are there any particular make of motherboard that I should avoid?

  I don't like to try to list avoids, you can get a brand name m.b. like
AMI or Micronics and be pretty safe. I get my 16MHz SX boards from
American Dealer SUpply and Support (408-720-9292) and the price just
went up to $385. WHile this is not a checp price, and they will try hard
to sell you their 20MHz model, I have used about a dozen of these and
run DOS, UNIX, and Xenix on it with success. I have not tried the 20MHz
board, as it is completely different and I want reliability rather than
speed in most cases. If I want more than that I would buy their 25MHz DX
board, not a fast SX.

| Are there any particular chipsets (e.g. TI, UMC, C&T, DTK) that I
| should avoid? Any praises as well? [Addresses & tel. nos. of suppliers
| would be most helpful.]

  The board I use has the NEAT chipset. If you like to be able to adjust
things the way you want you'll love it. It also has EMS support if you
like hardware rather than 386 (like QEMM) implementation.

| 2) Power consumption: how much can a 150 or 200W power supply handle? 

  I never found the limit of 200w unless I was running industrial
control. 150 should be fine for up to two HD and 16MB RAM + SVGA.

Note: 

(1) my experience is *only* with the 16MHz version of the board, not
the 20. The 20 is a new design made in a different factory. I'll try it
when I must.

(2) I had one board which was thermal sensitive. They gave me a choice
of shipping the old board and getting a new one by return mail or
getting a new one right then and billing my plastic if I didn't ship the
old one back.

(3) I have only talked to one technical guy and he knew what he was
talking about. The order takers don't strike me as technical (but they
don't need to be, do they).
-- 
bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen)
    sysop *IX BBS and Public Access UNIX
    moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -me