At 18:56 02/25/01, Chuck Finnigan wrote:
>I have the choice of purchasing either a PIII 600E 256K cache or PIII 500
>512K cache to upgrade my current Asus P2B. and what does the E mean?

Hi Chuck

I've done a lot of research on using my five P2B family boards with
recent PIII processors. Here's what I've found:

The PIII-600E is a "Coppermine" Pentium III. It's 256 KB L2 cache runs
at full speed (600 MHz in this case). The processor requires 1.65 volts.

The older technology "Katmai" Pentium III's 512 KB L2 cache runs at half
speed (a Katmai PIII-600's L2 would run at 300 MHz) and the processor
requires 2.00 or 2.05 volts.

The "E" at the end of the PIII-600E means it is a Coppermine and
distinguishes it from the Katmai PIII-600. (Yes, there are different
versions of the PIII-600. There are actually six different 600 MHz
PIII processors.)

The Coppermine is superior to the Katmai for two reasons. First, the
cache is faster. Yes, the Coppermine's cache is smaller, but 90% of
the time this is more than made up for by the cache's speed. Secondly,
the Coppermine runs cooler than the Katmai. (Coppermines typically give
off 18 Watts of heat compared to up to 30 Watts for Katmais.)

So should you get the Coppermine 600E?

Officially, you can run a Coppermine PIII on your Asus P2B motherboard
if it is a revision 1.12 board or later. (The motherboard revision number
should be stenciled on the board between two of the PCI slots or between
the last PCI slot and the first ISA slot.) The voltage regulator chips
on older P2B boards generally could not supply less than 1.80 volts to
the processor. (Recall that the Coppermine runs at 1.65 volts.)

When you put a Coppermine in a P2B, the processor automatically asks for
1.65 volts. If the P2B's regulator can't go below 1.80 volts, no voltage
at all will be sent to the processor and the system will not POST. Later
P2B boards with a different regulator can go down to 1.30 volts.

There is a way you can use any Coppermine (even up to PIII-1000) on even
an older revision P2B. You need to trick the voltage regulator into
supplying a voltage to the processor. Obviously you want this voltage
to be 1.80 volts (the lowest the regulator is capable of) and it will
be a bit high for the processor. However, Coppermines are spec'ed for
1.65 volts plus or minus 10% (that is, between 1.49 and 1.81 volts) and
1.80 is actually inside this range! If you get the most recent (cC0
stepping) Coppermine, Intel wants it to run at 1.70 volts and you see
that 1.80 is well within the 10% range of 1.53 to 1.87 volts.

You can override the Coppermine's choice of voltage if you use a FCPGA
370 pin Coppermine installed in a slotket adaptor. The Asus S370-DL
(or S370-133) slotket allows you to override the default voltage by
jumper on the slotket. You have no way of doing this if you have a
SECC2 (slot one) PIII. Note that there are other brands of slotkets
but you must be careful that they are of good quality and support
Coppermine PIII...not just Celerons. There's even a slotket from
Powerleap that has an on board voltage regulator that will supply
any voltage down to 1.50 volts. (Most slotkets simply tell the
motherboard voltage regulator what voltage is needed.)

Note: You need to flash your motherboard BIOS to at least
BIOS version 1011 for a Coppermine to work. See
<http://www.asus.com/products/Techref/Cpu/Coppermine/index.html>.
If you get a very recent cC0 stepping Coppermine, you might want
to use the latest 1013 beta BIOS from Asus's FTP site. This will load
the Intel cC0 microcode (errata for your PIII) at boot. The 1012
BIOS loads the cB0 microcode. (A feature of the PIII is that mistakes
in the silicon of the processor get corrected by code that is stored
in the motherboard BIOS. Things may or may not run properly without
these corrections. You can turn this feature on or off in your
motherboard's CMOS Setup.)

Final notes: You don't have to set the multiplier jumpers on your
motherboard when you upgrade to a PIII. Later PII and all PIII are
multiplier locked at the factory. These processors completely ignore
the multiplier signals sent to them by the motherboard.

The fact that your motherboard only goes up to a multiplier of 8X
does not mean that you can't use a PIII-850, 900, or 1000.
These processors are internally locked at 8.5X, 9.0X, and 10X and if
(for example) your board is set at 4X or 6X or 8X, it doesn't matter!

Now you know what the "E" at the end of the processor's name means.
Beware of PIII ending with "B". These processors run with a 133 MHz
bus speed. For example, a PIII-600EB runs at 4.5 X 133 MHz = 600.
In the case of the Asus P2B board running at 100 MHz, this processor
would run at 4.5 X 100 MHz = 450 MHz. (Remember you can't change the
multiplier.) If you buy a 600B for your P2B, it will run at 450 and
you'll be disappointed. If you try to run your P2B board at 133 (to
use a 133 MHz PIII), you'd be overclocking the BX chipset on the board
and the AGP video card, and you'd need PC133 memory. The AGP video
might give you major problems. An old P2B might not even be capable of
running at 133 MHz. (This feature was added with later revisions.)

Regards,
Bill

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