THE LUNCHBOX

Pentium3 in a Celeron-Only Socket370 Motherboard

By: Haut^Karl

Saturday, November 16, 2002

This was a relatively straight forward mod to put a Pentium 3 700 Mhz CPU in an Abit BM-6 motherboard. This board was designed to accept only Celeron processors (233 Mhz up to 1.1Ghz). Your board will also need to have a Voltage Regulation Module(VRM) that can actively output 1.5 volts and support a Front Side Bus(FSB) speed of 100 Mhz. If your board only supplies 2.0 volts, then this mod may not be for you(Powerleap does make the NEO-S370 and the PL-370-T which do the job nicely. Check their site for compatibility).

OVERVIEW:

While there were a few pin changes to the Pentium 3 chip, only 2 were critical to basic functionality in the original S370 boards. An unlabeled "key" pin was installed and the RESET pin was moved. So all we do is insulate or remove the key pin, AM2, and solder a thin wire from pin X4 to pin AH4.

DETAILS:

Celeron Socket

 

Pentium 3 Processor

 

Figure 1. Obtained from Intel Celeron .pdf pg. 97

 

Figure 2. Obtained from Intel Pentium 3 .pdf pg. 68

AN2: The ideal way to take care of pin AN2 is to pry open the S370 ZIF socket and use non-conductive tape on the contact. This is reversible and "believably" maintains your motherboard's warranty. An alternative is to cut off the AN2 pin from the processor(I did this when I had 16 of these mods to do) but this will void your processor's warranty. If you bought an OEM processor, your warranty has probably expired as it only lasted 15-30 days so who cares now!

X4-AH4: I soldered a thin piece of wire onto the back of the motherboard to make this connection. I have some very thin wire in the workshop, not sure what gauge this is, but a short strand of IDE cable will work or even a wire from an ethernet cable. This connection is not one of the high speed data lines the processor uses to crunch numbers so we are only concerned with making a basic connection. Length should be kept under 2 inches(5 cm). You could also use conductive paint but weaving in and out of the processor's pins is difficult and may make contact with unwanted pins.

RESULTS:

I have had this mod running in those 16 computers for 2.5 years now and not a problem yet. I did not reinstall Win 98 SE after this mod but I did have to upgrade the RAM to PC100 from the old PC66. If you are an overclocker, the Pentium 3 700 Mhz processor is a perfect candidate for 933 Mhz operation if your board supports the 133 Mhz Front Side Bus(FSB) speed and you install PC133 RAM.

DISCLAIMER: These mods will void your warranty. Do not attempt any of these if you fear you will not be successful.

We accept no responsibility for your errors, loss of hardware, software, data, or anything else for that matter.

2002 The LunchBox