First of all, please ntoe that all these hard modifications to your hardware will void the warranty for them immediately so do them at your own risk and with this knowledge!

Now for those relatively new to hard modifications, you are welcome to check out VR-Zone's mod guide.

Let's take a look at the 7600GT first:

With the back of the card facing you, look to the left of the card and you will see the area pictured above.

You can measure GPU Voltage and Memory Voltage from the points marked above with your multimeter. GPU Voltage runs at 1.3v in 2D mode and rises to 1.36v in 3D, while Memory voltage remains at 2.02v constant.

For VGPU increase, look for the resistor circled. Original resistance is 415 ohms. Use a sharp pencil and shade the resistor to decrease it's resistance. Dropping the resistance to 385 ohms from 415 ohms increases 3D voltage from 1.36v to 1.46v. Alternatively, you can solder a 10K ohms variable resistor across the resistor, set at maximum resistance of 10K ohms. Lower resistance to increase voltage.

For VMem increase, look for the resistor circled and labled VMem. Original resistance is 625 ohms. Use a sharp pencil and shade the resistor to decrease it's resistance. Every 25 ohms drop in resistance increases Memory voltage by 0.1v. Alternatively, you can solder a 10K ohms variable resistor across the resistor, set at maximum resistance of 10K ohms. Lower resistance to increase voltage.

Let's take a look at the 7900GT next:

With the back of the card facing you, look to the left of the card and you will see the area pictured above.

You can measure GPU Voltage and Memory Voltage from the points marked above with your multimeter. GPU Voltage runs at 1.2v in 2D mode and keeps at 1.2v in 3D, while Memory voltage remains at 2.02v constant.

For VMem increase, look for the resistor circled and labled VMem. Original resistance is 608 ohms. Use a sharp pencil and shade the resistor to decrease it's resistance. Dropping the resistance to 553 ohms from 608 ohms increases voltage from 2.02v to 2.23v. Alternatively, you can solder a 10K ohms variable resistor across the resistor, set at maximum resistance of 10K ohms. Lower resistance to increase voltage.

For VGPU increase, solder a 50K ohms variable resistor onto one end of the resistor shown above. Set at maximum resistance of 50K ohms. Lower resistance to increase voltage.

UPDATE:

For the VGPU Mod, a better method which allows more voltage has been discovered by the wisemen from the XtremeSystems forums. You can solely do the following without doing my previous VGPU mod.

First remove the resistor marked above and replace it with a 50K ohms resistor. This will give you 1.5v for VGPU.

If more voltage is desired, I suggest you move onto step 2: removing the 2 resistors marked to disable overcurrent protection for the card.

You can then move onto step 3: Soldering and connecting this point to any grounded spot. This will give you 1.6v.

Instead of step3, you can do step 4 if 1.7v is required.

Finally, we take a look at the 7900GTX Voltage mods. The mods are very similar to the 7800GTX 512MB mods.

Firstly, you can measure the GPU core voltage behind the card at the spot marked above. Default voltage in 3D is 1.4v.

Solder a 200 ohms variable resistor to the spot marked above and connect the other end of VR to ground. Set at maximum resistance of 200 ohms. Lower resistance to increase GPU voltage.

The Memory voltage can be measured as shown above. Default voltage is 2.12v. Join the 2 spots marked above with a 100K ohms variable resistor. Set at maximum resistance of 100K ohms. Lower resistance to increase Memory voltage.

I hope this has solved some of the voltage limits you face on this card. Be sure to have good cooling on the cards with these mods. Share your overclocking results with this board in our forums!

Be sure to check out how these cards compare to the rest of the other cards. Check out our Editors' Day coverage here. Read up on Quad SLI at the same time.

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