The VID mod

By: Haut^Karl

Sunday, November 10, 2002

We recommend the default voltage VID mod to get you going and prevent >2.0v initial power-ups. The VID mod will provide your motherboard with a minimum selectable voltage which can be adjusted higher if your board has this BIOS option. We had an adapter runaway to 2.2v before we applied the VID mod. "Default" means several things depending on which stepping of CPU you have.

If your CPU has default voltage of 1.45 or 1.475, then bridge AM34, AM36, AL35, AK36 on the motherboard, slotket or CPU to give you 1.45v. If CPU default is 1.475 follow the VID mod for 1.45v since most old VRMs can only adjust by +/-0.05.

The latest stepping CPUs, SL68P, runs at 1.5v default. If you were to apply the above VID mod to a SL68P, you would obtain 1.65v for a default voltage. The mod bridges VID0 and VID1 while the CPU has VID2 bridged internally. Add those together when you install the CPU, and you end up with VID1+2+3=1.65v. You can insulate AL37 and perform the previous paragraph's VID mod or tie AK36 to Vss and you will get 1.5v default

Some Celeron-only boards will not produce voltages below 1.8v so you are basically out of luck as far as modding goes. You need some very good cooling to run a Tualatin CPU at 1.8v. Try PowerLeap for their Slot1 and Socket370 adapters for Tualatin Processors.

Depending on your board, you might be able to adjust your voltage in the BIOS. If not, use Diagram 2 below to see which pins you need to bridge with AM34 to get the voltage you want.

Diagram 2


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