Introduction

When DFI released the LANPARTY UT nF3 250Gb board, all overclockers had it on their, “must have” list. The board had more tweaking options than any other board available for the Athlon64 CPUs.

But there was one thing that was a bit sad:
Soon after its release, some eager BIOS modders discovered that the board had hidden options in BIOS for up to 4V VDimm (unofficial modded BIOS versions are available). First this seemed to be very good news, but unfortunately DFI had decided to generate VDimm using the 3.3V-rail, thus max. useable VDimm was still 3.1-3.2V (like in the official BIOS versions). One way to get higher VDimm was increasing the 3.3V-rail of your Power-Supply, but that led to new problems in some cases. With the modded 3.3V-rail, users complained about cold boot problems (the reason for that “bug” is that the board always uses 2.5V VDimm for the first start on a cold boot, instead of using the value set in BIOS) and a max. VDimm of ~3.5V regardless of how high they had set their PSU’s 3.3V-rail (any VDimm higher than ~3.5V led to no boot at all).

Now that is where my mod comes into play. As I already said, the problems with high VDimm were mainly caused by the increased 3.3V rail. My solution to this is simply using the 5V-rail instead. To make this possible you need to do major modifications to your motherboard, and your warranty will be void for sure, but if you are a real enthusiast, this won’t bother you at all anyway.

Required parts

Here are the parts that you will need for this modification:

• a good soldering iron (Ersa 25W in my case)
• rosin core solder and solder flux (for example "colophony")
• some cables (I used 1.5mm diameter cabling, made from copper strands, normally used for hi-fi systems)
• some heatshrink-tubing and hotglue
• and perhaps some isolating protection lacquer
• heatsinks and thermal epoxy (an alternative to the thermal epoxy would be to buy 5-minute two component epoxy and then mix that with thermal compound; I often used that method and it always worked fine)
• either one 100K (trimmer-) potentiometer or two 50K (trimmer-) potentiometers for the hardware VDimm-Mod

First, cut off or break off one of the two outer legs of all potentiometers, because only two contacts are needed [the middle contact (signal) and one of the outer two pins (ground)]. The third one is useless for this mod. It could be in your way while working on the other two legs, could interfere with some parts on the motherboard, or could even cause a short circuit in the worst case.

Afterwards, adjust the potentiometer(s) to the maximum resistance. Those are the values to start with - they are very important!