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Subject:
From:
Bill Cohane <[log in to unmask]>
Reply To:
PCBUILD - Personal Computer Hardware discussion List <[log in to unmask]>
Date:
Fri, 20 Apr 2001 09:58:46 -0400
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At 23:07 04/15/01, Gary Cassidy wrote:
>I asked at the time that a Motherboard with the capacity to handle
>up to a PIII be installed. The Motherboard is a 440 BX by ASUS...
>I have my eye on an Intel Celeron 700 PGA 128K/66 (I'm a cheapskate
>and  have no need for Top Of The Line)...
>Does anyone see any conflict with the Motherboard I have?

Hi Gary

The Celeron 700 (actually any Celeron faster than 533) has the
same core as the Coppermine PIII.

This means that it runs at 1.65 or 1.70 volts. Most BX boards
made by Asus were meant for processors of the PII and Katmai
vintage PIII that ran at 2.00 (or 2.05) volts. You'll need to
know what model motherboard you have. You can read this
information from the screen when the machine starts to boot.
(Hit the pause key if you need to freeze the screen. Write
down the board model number and the BIOS revision number...
usually something like 1012 or 1013...after the Award 4.31
stuff. Hit any key to continue booting after you save the
information.)

So your motherboard may very well have a voltage regulator
that can't go as low as 1.65 bolts. You should go to
http://www.asus.com/products/Techref/Cpu/Coppermine/index.html
and see if your motherboard will work with Coppermines.
(You'll likely see that your board is Coppermine ready only
if it's revision number is high enough and if you have a very
recent BIOS update.) The BIOS update can be done (must be done!)
but you may have a motherboard with too early a revision
number. (The motherboard PCB revision is usually stenciled on
the motherboard between two of the PCI slots.)

Another way to tell if you can go as low as 1.65 volts is to
look at the markings on the voltage regulator chip on your
board. (It should be near the capacitors and inductors near
the processor slot.) If you can identify this chip, write
down the number on its back and email me. (Some older boards
actually had the more expensive voltage regulators...maybe
Asus had trouble getting enough of the cheaper regulators
at certain times.) From the chip number, I can tell you if
your regulator is specified to go as low as 1.30 volts or if
it can only go as low as 1.80 volts.

Worst case, suppose your board only goes as low as 1.80 volts.
You can run your processor at 1.80 volts and probably be okay.
When Intel specifies that a processor is to be run at 1.65
volts, they mean 1.65 +/- 5% or (maybe) 10%. Say you get a
recent Celeron that runs at 1.70 +/- 5%. This means between
1.615 and 1.785 volts. 1.785 rounds to 1.80 volts. If the
specification is +/- 10%, you are inside the specifications
when you run even a 1.65 volt Celeron at 1.80 volts. My point
is that 1.80 volts is not so far off.

Whatever you do, you're going to need a Coppermine enabled
Slotket adaptor card. (The Celerons are FC-PGA chips and you
have a slot-one board.) Not all slotkets work with Coppermine
processors. Also, not all newer slotkets work at 66 MHz or
even with Celerons. You going to have to plug your Celeron
into the socket on the slotket and then fit the slotket into
the "slot-one" on your motherboard.

Here's another way to find out if your motherboard can go
down to 1.65 (or 1.70) volts. First try the Celeron with the
sloket's voltage jumpers set to "CPU Default". (Most slokets
do not have a voltage regulator on board and they can only
tell the motherboard what voltage to use.) With "CPU default"
selected, the slotket allows the processor to tell the
motherboard voltage regulator what voltage to use.

If your motherboard fails to boot at "CPU Default", (you just
see a blank screen when you try to boot), then power down and
take out the slotket. Change the slotket voltage jumpers to
1.80 volts and then put it back. This over-rides the
processor's voltage request and asks the motherboard for 1.80
volts.

When the motherboard voltage regulator is asked for a voltage
outside its range, it simply shuts down and the machine can't
boot. If you ask the voltage regulator to provide 1.80 volts,
it will happily provide this and the machine should boot.

Since 1.80 volts is a bit high, you should be sure to have
proper cooling for the processor. This means *not* using a
really cheap heat-sink/fan combination. (Be sure to use
heat-sink grease/compound properly applied between the
processor and heat sink.)

Finally, your motherboard probably won't offer a 10.5
multiplier. But since Intel locks the multipliers internally
for all Celerons and PIII, they ignore the multiplier jumpers
on the motherboard. So there is no need to worry. Plenty of
people are running even PIII-1000 processors on Asus BX boards
that only have multipliers going up to 8X. Be sure you have the
latest BIOS. They are available for download from:
ftp://ftp.asus.com/Pub/ASUS/mb/slot1/440bx/
ftp://ftp.asuscom.de/pub/ASUSCOM/BIOS/Slot_I/INTEL_Chipset/i440BX/
ftp://ftp.asus.com.tw/pub/ASUS/mb/slot1/440bx/
The German site usually posts the latest versions before the
US or Taiwan sites. (Yes, the screens will be in English.) Be
sure to get the Award flash program as well. Don't even think
of trying the new Windows flash program. It has bugs. Flash after
booting from a DOS or startup diskette.

Regards,
Bill

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