Overclocking PIII

 

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Overclocking the Pentium III / Celeron II (socket 370, FC-PGA, FC-PGA2)

What is the problem ?

Why should anybody overclock a celeron or pentium III processor ? And why is this not possible on all mainboards (but could be done after reading this page) ? These questions appear if somebody is thinking about buying a processor but does not want to spent much money for it. Some people already talked about overclocking the CPU. But how ?

What is the solution ?

Some guys already bought a overclocking capable motherboard from Abit or Asus. May be they are lucky with their boards...
But what's with most of the other ones, who can't get such a board ? First, take a look into your mainboard manual. If your mainboard supports raising the core voltage with the help of jumpers or bios settings, that would be fine. May be the range is not high enough for raising the core voltage ...
So you have to find out how you can raise the core voltage without modifying too much.

Tell me what can be done in detail ...

There are several ways how you can solve the problem. Buying a new mainboard for example (just kidding). So there is now a cheap and easy way for doing this. There are 4 pins which are controlling the adjustage of the core voltage, so called 'voltage identification' pins.
There is a table which shows you the available combinations:
 

VID3 VID2 VID1 VID0 Vcc Core
OPEN OPEN OPEN OPEN 1.30
OPEN OPEN OPEN GROUND 1.35
OPEN OPEN GROUND OPEN 1.40
OPEN OPEN GROUND GROUND 1.45
OPEN GROUND OPEN OPEN 1.50 *1)
OPEN GROUND OPEN GROUND 1.55
OPEN GROUND GROUND OPEN 1.60
OPEN GROUND GROUND GROUND 1.65 *1)
GROUND OPEN OPEN OPEN 1.70
GROUND OPEN OPEN GROUND 1.75
GROUND OPEN GROUND OPEN 1.80
GROUND OPEN GROUND GROUND 1.85
GROUND GROUND OPEN OPEN 1.90 *2)
GROUND GROUND OPEN GROUND 1.95
GROUND GROUND GROUND OPEN 2.00
GROUND GROUND GROUND GROUND 2.05

*1) Defaults for Celeron-II
*2) possible combination for the suggested solution


What have i to do now ?

Because you can't connect a pin which is already connected to ground to a "high" without cutting the pin from the CPU, there are only a few possible combinations (changes are red):

VID3 VID2 VID1 VID0 Vcc Core Pins to connect
OPEN GROUND OPEN OPEN 1.50 No pins, default
OPEN GROUND GROUND GROUND 1.65 3 Pins
GROUND GROUND OPEN OPEN 1.90 2 Pins

 
Here shown the pin layout of the fc-pin grid array socket:
 

Here is a magnified view:
 


And here is the picture from the CPU after wiring the 2 pins together now:
 

Many people told me that raising the voltage to 1.65V is not enough, so I decided to take the 2-Pin solution (1.9V).
If you can get a better cpu cooler, take it. Every step for a better cooling results in a longer life for the CPU.

Hint: For me the original Intel heatsink/fan matches my requirements for cooling, I didn't recognize any significant increase of the temperature.


Other useful infos:

It is possible to raise the whole core voltage range with the method described above. Often there is a possibility in the BIOS (Softmenu or similar) to set up this voltage. You will raise the upper value of the range too, so you start with a lower value, increase the voltage in small steps until you have success.


Prerequisites:

A lot of time - more than 30 minutes ;-)
A thin (flexible) copper wire
The CPU itself


Well known Disclaimer:
The workaround was tested for a long time. Regardless of this, I couldn't give you any guarantee of correct function nor any guarantee of data integrity after you make the described changes.

Here are several (good) links to the subject above (hopefully not changed, if so, try archive.org):

Bump that voltage
Overclocking FAQ
Powerleaps FC-PGA2 adapters

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