How to make VGA Dummy plugs

[Brian@ASUS]

Dummy plugs are used to trick the computer to think there are additional monitors being detected on a MultiGPU folding solution. The GPU clients will not let you fold unless it detects a monitor. and if you dont have multiple monitors, you will need dummy plugs to make it think it does.

1: You will need 1x DVI to VGA converter and 3x 68Ohm resistors (which can be purchased from Radio Shack) and bend the ends like so. You may need to cut then ends off to make them even.


2: Plug the first one in from the top right to the middle right holes.


3: Plug the second resistor backwards so there is no direct contact with the first resistor. It should go into the 2nd top right to the 2nd middle right.


4: Plug the Third resistor forward so there is no contact with the second resistor. It should go into the 3rd top right to the 3rd middle right.


5: Plug it in to your GPU. 1 Dummy plug is needed for every GPU being used to fold, except for the first card which is obviously going to your monitor.

[martin_metal_88]

Great guide Brian! I just have a little thing to add. For those like me who have a box of resistor and don't know how much Ohm they are, here is the color code. You don'y have to worry
about multiplier and tolecerence since the load you are gonna put in with the dummy plug is so little.
http://www.boxofohms.com/ResistorColorCodes.jpg

[AyeYo]

I can confirm that only two resistors are necessary (plugged in as shown in pic #3). They also don't have to be exactly 68ohm, anything in the range from like ~50-120 is fine.

[V2-V3]

Brian, I made a post in the past on this

If you are having Multi graphics card configuration issues like overclocking your second graphics card, or even problems seeing the second graphics card,this post is for you!

Go to registry and disable Ulps:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Cl ass\{4D36E968-E325-11CE-BFC1-08002BE10318}]

and change "EnableUlps" to 0 under the 0000 and 0001 or 0003 keys.

If this dos not work for you try the next method

Another solution is making and installing a "VGA Dummy". The purpose of this is to 'Fool' the graphics card into thinking there is a monitor connected to it. Here is a quick and simple guide to making the dummy dongle.

VGA dummy plugs were made popular by folders. They are electronic devices used to fake the presence of a monitor attached to a VGA or DVI output port so that the graphics driver can be forced to initialize the corresponding GPU in order to be able to run GPGPU programs on it —Folding@Home being one of the most popular. A dummy plug works by simulating a resistive load of 50-150 Ω on the analog red, green and blue VGA signals.

It made sense for drivers to not enable a GPU when no monitor was attached to it. But since the rise of GPGPU applications, graphics vendors AMD and NVIDIA realized that this behavior was inconvenient. At least with the most recent Linux drivers, dummy plugs are not necessary anymore. However Windows still requires dummy plugs.



VGA DB-15 wireing diagram for the VGA Dummy


RadioShack does not carry "75 ohm" resistors, however any resistors from ~50-150 ohms will work for what we want. RadioShack does stock 68ohm resistors and they will work.

Easiest connector to modify is the DVI to VGA adapter



Here we see the 15 pins that make up the DB15 VGA connector



As can be seen in the picture, I alternated the orientation of the actual ceramic resistors in order to create a "built-in" seperator or divider to help keep the leads from contacting each other.



rebooted with the dummy installed and got exactly what I needed