Voltage MOD for PIII Motherboards - The Wire Trick

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Update 9/10/01:

I received a couple of questions regarding lowering the voltage in BIOS after performing The Wire Trick. This is not possible (at least not on the ASUS CUSL2 series). It is only possible to raise the voltage in BIOS and
therefore this is something that should be considered before performing The Wire Trick and deciding on which voltage that should be hardwired.

However, if you have a cA2 or cB0 processor, then your options are limited
and you should seriously consider if you have sufficient cooling for running your processor at 2.00V or 2.05V. You cannot lower the hardwired (or “wire tricked”) voltage so it is all or nothing.

Also, if you have questions about The Wire Trick not covered in the article I would recommend that you post your questions HERE.

This is a dicussion about The Wire Trick and there are plenty of helpful
people to help you with specific questions.

Why do we need The Wire Trick?

A lot of people with a CUSL2 series motherboard suffer from what is generally known as “The Cold Boot Problem”. The Cold Boot Problem comes into play when you have a processor that needs more than its default voltage to POST (initial Power On Self Test) at a certain speed.

Although you can select voltages up to 0.3V higher than the default in BIOS, the CUSL2 series does not apply the selected voltage until after the computer has POSTed. This means that your computer will hang during POST because your processor does not receive the required voltage.

Example

My Pentium III 700 MHz needs 1.95V to POST at 980 MHz. Since my CUSL2 motherboard only applies the default voltage of 1.65V during a cold boot POST, my computer hangs every time I turn it on. I definitely suffer from The Cold Boot Problem. The only fix for this is to POST at a lower speed and then reset the computer once it starts loading the operating system.

When the computer restarts, you enter the BIOS and change the speed to the desired setting. This is a bothersome way to start your computer, though, so some smart people have dug into Intel’s datasheets and come up with a simple modification that solves the problem.

This modification is known as “The Wire Trick”.

People without a CUSL2 series motherboard can also benefit from this modification since it allows them to raise the voltage beyond the normal max in the BIOS (most BIOSes allows for voltage regulations of +0.15V to +0.30V)

What is The Wire Trick

It is basically a very simple procedure that will trick your processor into thinking that it has a different default voltage. The name comes from the fact that the only thing needed is a THIN piece of copper wire.

How To Do The Wire Trick

Before we start doing The Wire Trick we need to a few things:

  • An FC-PGA Pentium III and motherboard;
  • A thin piece of copper, silver or gold wire;
  • This article for reference;
  • Guts to try it.

Note that this modification is not without risk. Although a successfully performed wire trick is easy to undo, you could fry your processor if you do not take care and do it correctly. Also, please note that I cannot be blamed for any damage that YOU inflict on your hardware, yourself or others.

As you can see, this mod is a very cheap one and if you suffer from The Cold Boot Problem, then it will definitely make your life easier :).

The technical information that we need to perform The Wire Trick can be found within the Intel ® Pentium ® III Processor for the PGA370 Socket at 500 MHz to 1.13 GHz Datasheet. The information we are looking for is found on pages 21 (Voltage Identification Definition) and 68 (Intel Pentium III Processor Pinout). I have included copies of the tables and diagram in this article.

I will now describe the procedure using my own Pentium III 700MHz (SL45Y, cB0 stepping, Batch # 7029A625) as an example.

WARNING: Before you start doing The Wire Trick please set your processor voltage to the lowest possible in the BIOS. This is important because failing to do so may damage your processor!

Step One:

First we must determine the default voltage of the processor. This is easy because it is printed on the processor along with a lot of useful information. Look at the black label on the processor and locate the default voltage at the end of the second line.

As mentioned above, my processor is an SL45Y (end of third line) with a default voltage of 1.65V. This information can be used together with the Intel ® Pentium ® III Processor s-Spec Information to find the processor stepping as well. We do not need to know the stepping in order to do The Wire Trick, but you may have noticed that it is an often-used term and it will be useful for you to now it.

Def ID

Looking in the table, we can see that my processor is a cB0 stepping processor. Note that voltage is not displayed directly in the table. Rather, it is represented by note in the right most column.
{mospagebreak}

Anders Petersen

Step Two:

Intel Pentium III processors have their default voltage determined by a specific combination of open and closed circuits. This might sound impossible to alter, but actually it is quite easy.

Four pins (VID0, VID1, VID2 and VID3) on the bottom of the processor can either be connected to (closed) or disconnected from (open) a fifth pin called VSS. Depending on which pins are connected, the voltage can be determined.

Let us have a look at the Voltage Identification Definition table.

Volt ID

The table describes the different combinations possible (1=open and 0=closed) and we can use it to determine how my current pin configuration is. Unfortunately, the table shows that three pins (VID0, VID1 and VID2) are closed internally (inside the processor :() and therefore are impossible to change.

This leaves only one option:

I can connect VID3 to VSS and thereby change my voltage to 2.05V. This is a huge step up and I would not recommend it unless you have very good cooling. Since my calibrated full load temperature is 35°C, I have decided that it is safe for me to use 2.05V. You should read the “Important Considerations” at the end of the article for some input on what is safe for you.

Possible VID pin configurations


Stepping

Default Voltage

Wanted Voltage

Pins Closed Internally

Pins to Connect to VSSL2

cA2/cB0

1.60V

1.65V

VID1, VID2

VID0

cA2/cB0

1.60V

2.00V

VID1, VID2

VID3

cA2/cB0

1.60V

2.05V

VID1, VID2

VID0, VID3

cA2/cB0

1.65V

2.05V

VID0, VID1, VID2

VID3

cC0

1.70V

1.75V

VID3

VID0

cC0

1.70V

1.80V

VID3

VID1

cC0

1.70V

1.85V

VID3

VID0, VID1

cC0

1.70V

1.90V

VID3

VID2

cC0

1.70V

1.95V

VID3

VID0, VID2

cC0

1.70V

2.00V

VID3

VID1, VID2

cC0

1.70V

2.05V

VID3

VID0, VID1, VID2

cD0

1.75V

1.85V

VID0, VID3

VID1

cD0

1.75V

1.95V

VID0, VID3

VID2

cD0

1.75V

2.05V

VID0, VID3

VID1, VID2

If you have a cD0 stepping processor and find it hard to connect VID1 directly to VSS, then you can choose to connect it to VID0. Because VID0 is already connected to VSS this will give the same result.

Step Three:

The Voltage Identification Definition table stated that I must connect VID3 to VSS to attain the 2.05V. So how do we do this?

First we must identify where VID3 and VSS is located so let us take a look at the Intel Pentium III Processor Pinout.

Pinout

Alright, maybe some of you need reading glasses to read the text, so let us zoom in and have a look at the interesting area:

Pinout Close

A bit easier to read now? You can use the overview to align you processor correctly. We are getting to the exciting part and mistakes here could potentially turn your processor into a very expensive key chain!

{mospagebreak}

Anders Petersen

Step Four:

We have now identified the placement of the pins that need to be connected to VSS and we only need to decide now on how to do it. There are a couple of different approaches, but I believe that the most common ones could be called The Wrapping Method and The Pinhole Method.

The Wrapping Method

This is not the method that I would recommend the most, but a lot of people have used it successfully. I consider it a bit more risky than The Pinhole Method and I have heard of people frying their processors using this method.

The procedure is very simple. Take the wire and wrap it around the VID pin a couple of times. Then lead the wire to the VSS pin and wrap it around that one too. Remove any excess wire.

MAKE SURE THAT THE WIRE ONLY TOUCHES THE CORRECT PINS!

One of the reasons I do not like this method is that the rolled up wire can cause the processor to tilt slightly in its socket. This may cause you to lose perfect contact with heatsink and thus decrease your cooling performance considerably.

Furthermore, I do not feel convinced that the wire cannot shift during processor installation and thereby come in contact with other pins. This could kill your processor!

The Pinhole Method

This is way I chose to perform The Wire Trick and therefore I am able to present pictures on how to do it.

The most important part of the pinhole method is to correctly identify which pin holes are for which pins. This may sound trivial, but you should check and recheck that you got it right because errors can be fatal for your processor.

Let us have look at the socket first:

Socket 370

The pinholes for the VID and VSS pins have been color coded so you can easily locate the correct ones. You can compare the pinhole positions with the processor pinout above and double check that I have located the correct pinholes.

Now take the wire and make a piece that is about 10-12mm long. Bend it into a U-shape and “drop” it into the pinholes that are to be connected. Repeat this if you need to connect more than one pinhole.

What I like about this method is that it prevents the wire from causing the processor to tilt in the socket. By cutting a small groove between pinholes, we can place the wire safely in this groove. The bonus is that this also prevents the wire from shifting and coming into contact with other pins.

Step Five:

We have now performed The Wire Trick and can begin to enjoy turning on the computer without having to restart it because of The Cold Boot Problem.

If you don’t see a changed default voltage in the BIOS, then you might have used a too thin wire. I had this problem initially, but after replacing the wire, I had 2.05V. This might only apply if you have used The Pinhole Method.

Important Considerations

Please note that the BIOS will allow you to add 0.3V to the default voltage even though this exceeds Intel’s specifications. Doing this is definitely NOT recommended and involves a high risk of frying your processor. This is also why you must select the lowest voltage in the BIOS before you commence doing The Wire Trick.

For example, if you have selected the highest possible voltage in the BIOS, then upon booting after performing The Wire Trick, your processor will receive the new voltage plus 0.3V – this could kill your processor on the spot!

You also need to consider what the highest NEEDED voltage is. If you have a cC0 or cD0 stepping processor, then you have more voltage options than I do with my cB0 processor. cC0 processors (default voltage of 1.70V) can be “tricked” in 0.05V increments all the way up to 2.05V and cD0 processors (default voltage of 1.75V) can be “tricked” in 0.10V increments also up to 2.05V.

When deciding on how much voltage you need, you shouldn’t “trick” your processor to the voltage needed to be stable in Windows. Rather, you should “trick” it to the voltage needed to POST and then raise the voltage the rest of the way using the BIOS.

There is also the topic of what a safe voltage is. You may hear all the time that overclocking shortens the lifespan of your components, and this is true. However, not many are aware of WHY this is the case.

When you overclock your components, they run faster and HOTTER. If you then apply even more voltage (like we do here), they will run even hotter. Most people think that if it is stable then it is cooled adequately. This is not entirely correct.

Cooling serves two purposes: To keep your computer stable and to reduce the risk of electromigration. You can read about electromigration here, but the short story is that high voltage and heat causes the tiny wires inside to “break”. The only way of reducing the risk of this happening is to run your computer as cool as possible.

I would estimate that if you can keep your full load temperature (use a program like CPUburn to test full load temperatures and calibrate the internal thermal diode to make sure it is accurate) below 50°C, then it would be OK to use 1.85V. If you can keep it below 45°C, then 1.95V may be OK. Only if your full load temperature is below 40°C should you use 2.05V.

Finally, I hope that this article can help out a lot of people who have The Cold Boot Problem and who have problems grasping what exactly The Wire Trick is and how it can be performed. I would also like to thank the members at AsusBoards.com who provided me with feedback. Patentman, especially, provided invaluable feedback and ideas for improvement when I was writing this article.

Happy overclocking!

Anders Petersen
(aka StarTraveller at AsusBoards.com)

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