What is Volt-modding ?

Disclaimer: Volt-modding your hardware may void the warranty, cause overheating, instability, or even permanent damage. Please volt-mod on your own risk. Certain other procedures mentioned in this article may also cause damage, data loss, or voiding of warranty. Those referenced procedures include skills in electronics and require basic knowledge of hardware components.

A volt-mod is a modification to a piece of hardware — mostly done by a physical access to the device — allows more voltage to run through that certain hardware. Motherboards and Graphics cards alike can be voltmodded or V-modded. In overclocking scenarios, the more power the device demands, the more voltage it needs. In Linux world, there are but a few (outdated) applications that allow users to tweak voltage values (software access to the device). That’s why you need to do it manually, either writing the software or Volt-modding the hardware by yourself.

After all you are a Linux user, which means you love to tweak settings and explore new things.

First of all, you need to know what’s the hardware you need to modify. Well, this circuit is called Voltage Regulator

What is a Voltage Regulator ?

In simple words, Voltage regulator is a complex circuit found in devices such as computer power electronics, where they stabilize the DC voltages used by the processor and other elements.

How ti works ?  I will try to put it as simple as I can because no all readers have the required knowledge background in electronics. So, imagine voltage regulator as a black box that takes (input R) X Voltage and X Ampere from the left side and in return it gives (output C) Y Voltage and Y Ampere. That’s all you need to know.

What tools do we need ?

  1. Soldering iron is a hand tool used in soldering and maybe the favorite tool of any guy who loves electronics. You need a cheap, 15 – 30 Watt soldering iron but with a very thin tip. You don’t need more watts or you gonna damage your hardware permanently.
  2. Solder a fusible metal alloy used to join together metal workpieces. Pay a visit to your local electronics shop and ask for solder commonly used for electrical soldering. I use 60/40 Tin/lead (Sn/Pb). Anything else would be much bigger–thicker– for such a “surgery job”, making the task even more difficult to achieved.
  3. Digital Multimeter is a hand-held device that combines several measurement functions in one unit. A typical multimeter would include basic features such as the ability to measure voltage, current, resistance, and Diode voltage. Please read its manual first, I am not going to explain you how it works or how to you use it properly.
  4. Patience and steady hands are needed here. Soldering iron is a tool that generates heat… if you scared, don’t use it… if you underestimate the danger you ‘re doomed to fail. So be careful and don’t rush things.

 

Let’s start volt-modding

1. Step: Look for the voltage regulator chip

Usually, this chip is located near to the CPU slot (in case motherboard). However, if you are going to volt-mod your Graphics card, there is not a standard place for finding its location. You have to search along the PCB for a chipset similar to this:

The image shows the Voltage Regulator of nVIDIA GeForce 8800 GT/GTS/GTX/Ultra for Core speed

2. Step: Identify Voltage Regulator and google for pinout scheme

There are several letters and number that make no sense to anyone, that’s why Google is your friend. You have to find out which is the appropriate pin layout for your particular chip. Here’s an example showing how a pinout looks like:

Note that there are two Voltage Regulator chips in GPUs: Vgpu and Vmem, for core and memory respectively. From my experience, Vmem is located near the VRams and has more voltage than Vcore.  The Vgpu is located near the middle and has square size with many pins surrounding it.

3. Step: Locate the FB/V-Sense pin

Supposing that you’ve already found the pinout scheme that is identical for your voltage regulator chip, now you have to locate a special pin. This pin is named as FB (shortcut for Feedback) or VSense. The naming (FB) describes its function. As I said earlier, Voltage Regulator is like a black box that takes X volt/ampere and outputs Y volt/ampere. The chip has an inner mechanism that checks for Over Current situations (OVP). Simply put, there is a factory-defined voltage value (known as reference voltage or max threshold) that produces a fixed (constant) voltage value irrespective of the loading on the device. The voltage regulator operates by comparing the actual output voltage to this fixed reference voltage. Any difference is amplified and used to control the regulation element in such a way as to reduce the voltage error. This forms a negative feedback control loop; increasing the open-loop gain tends to increase regulation accuracy but reduce stability.

system_feedback

For example, if the actual output is 6 Volts but the desired output is 5 volts (reference), the negative feedback returns -1 treated as error. Then the voltage regulator fixes its output ( 6-1=5). That’s the basic principal.

Up to this point, you have to fool this feedback mechanism; in other words cheat. You are going to mod this feedback mechanism to understand your desired voltage as its reference voltage value. In that way, the voltage regulator will compare that actual output to your fixed reference voltage instead of its factory-fixed reference voltage value.

Optional Step: Locate a nearby resistor that has 0 resistance with the FB pin; this means they are equally connected to each other. A resistor soldering-joint is way more easy task for beginner’s without prior experience in soldering.

4. Step: Measurements

Given that we have already found the FB / VSense pin, now you have to use your DMM and measure the resistance from this pin to the Ground (GND). Make sure you are aware of identifying ground spots in your hardware or  There are a ton of grounding points on the card, but the one that is easiest are the screws that hold on the HSF.

5. Step: Do the Math

Multiply the number from Step 4 by x20, then you will now what Trimmer you need to buy for that job.

6. Step: Buy the VR

Given that we know what trimmer we need, then go again to your local shop for electronics and ask for it. Just in case you are never heard of trimmer before, this is a variable resistor with 3 pins and a screw for adjusting the resistance value. For instance, I used a 1K-Ohm 15-Turn PC-Mount Cermet Potentiometer/Trimmer (but that’s only for my GeForce 8800 GTS). For this mod you are going to use only two pins.

heat shrinkable: is like a macaroni which resizes (shrinks) when you apply heat on its surface. We need this in order to insulate the trimmer pins  in order to avoid making unwanted connections, and risking shorting your card.

wire-cable : I guess we all know what it is 

7. Step – Preparation
Okay, now you have all the tools and accessories required to do the task. Start off with the trimmer and adjust it up to its maximum resistance value. Make sure you know what direction you need to turn the knob to raise and lower the resistance. Remove (cut) one pin and use the other two: the one in the middle and the other one nearest to the knob, so the more you screwing the higher resistance it gets. Use your multimeter to make sure you are turning the knob to the right direction.  Then, solder two separate cables to its pins and use heat shrinkable for insulation purposes.

8. Step – Soldering
Take the trimmer and solder one cable to the FB spot and solder the other one to the Ground . It would be better if you’ve found a GND spot near the FB spot in order to avoid using long cable but short ones.

This is my first volt-mod applied into a GeForce 4 Ti 4200. As you can see I wrongly used too long wires.

 

examplevoltmod

 

That’s a proper V-mod. Short wires, nice and easy access to the molex:

betterone

To check if you are making contact with both connections, use your multimeter to measure the ohms between the 2 pins on the VR. Even though you set it to X Ohms, you should see Y ohms — a value much lower than X, due to the fact you are simply hooking up the VR to run in parallel. his page may help explain it better: http://www.1728.com/resistrs.htm. Now we are ready and the modding is over.

To increase the voltage farther, just turn the VR (trimmer knob) to a lower resistance ( Be sure to measure the volts constantly, as to avoid overvoltage).

multimeter

PS: There are several ways to V-mod your GPUs but this guide explains you the basic principles you need to know before you google around. Die hard modders use their HB pencils, drawing 2 or 3  lines upon the resistor in order to lower it’s resistance. Crazy !

Happy Vmodding 

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