I don't actively monitor this thread anymore, so if you have any questions, post and notify me through PM
The Simple and Concise 7900GT Voltmod Tutorial, webpage-ified, courtesy of keysplayr2003
I know a lot of newbies are looking for a step by step tutorial on how to do their 7900GT voltmods. It seems like wherever you go you have to either trudge through circuit diagrams, 10+ pages of discussion, awful pictures, or chaotic directions to get this information.
Here it is, all in one place. These steps have all been done by me and have been CONFIRMED to work 100%.
NOTE: The RAM vmod and the GPU vmod are completely seperate things. Increasing the voltage on the RAM will allow you ONLY to overclock the RAM higher than on just stock volts. Increasing the voltage on the GPU will allow you to ONLY overclock the GPU higher than on just stock volts. You can certainly choose to just do a single vmod, like the one for the RAM, but you'll only get benefits for the RAM by doing this.
Doing both the GPU and the RAM vmods is basically a double whammy, and lets you overclock both higher than normal.
Disclaimer
Anandtech and I are not responsible for screwups that result from this guide
Tools:
Digital Multimeter - $20 at RadioShack Brick and Mortar stores or $3 at Harbor Freight online or at Harbor Freight B&M locations. If you get the RadioShack multimeter make sure to purchase a 12V battery at the same time because it doesn't come with one. The Harbor Freight one comes with a 9V battery.
Conductive Pen - $13 at RadioShack
Pencil - a regular #2 pencil will work. Mechanical, wooden, it doesn't matter. I used a mechanical pencil.
Acetone (nail polish remover, no additives) or denatured alcohol or at least 70% Isopropyl Alcohol - For use in erasing the conductive ink if you mess up. Both available at Walmart or drug stores. Denatured alcohol is in the paint section.
A new heatsinkfan for the core, and eight BGA ramsinks for the RAM
Picture of the 7900GT so people can get their bearings.
RAM voltmod: (pencil, incredibly easy)
RAM Voltmod Section Blowup
1. Locate the RAM voltmod section on your 7900gt and take out your multimeter. Verify that the resistance across the circled resistor is 608 ohms.
Multimeter newbies: Switch your multimeter to the OHM section and put the red tester lead on the left side of the resistor and the black tester lead on the right side of the resistor, or vice versa. Play around with the OHM switch (200, 2K, 20K, 200K, etc) until you get a reading of 608 on your display.
2. Lightly shade the circled resistor with the pencil, from end to end.
3. Shade or erase until the resistance across this resistor has changed to around 553 ohms (check with multimeter).
GPU voltmod: (conductive pen)
GPU Voltmod Section Blowup
Getting to 1.5V: The 7900GT core comes stock at 1.2V. A regular GTX does 1.4V just fine. 1.5V is also fine.
1. Take your conductive pen and carefully trace the red lines in the above picture. It's best to trace a few practice lines on paper to get a feel for the pen's ink flow. It's harder than it looks if you do it freehand. My lines, if you can even call them that, are definitely not pretty, but they still work. If you want to get straighter, more defined lines, use masking tape to outline where you want the lines to go, and paint over that outline with the pen.
2. If you messed up, use acetone or isopropyl alcohol to dissolve the ink, wipe clean with a Q tip or section of paper towel, and redo.
Getting to 1.4V:
Trace the 1.4V line in this picture.
Getting to 1.55V:
Trace the line in this picture.
Verifying that the Mods Work (testing the voltages)
1. Put your card back into your computer, being careful not to touch the conductive ink or the resistor.
2. Turn your computer on. Measure the GPU voltage and the RAM voltage at the circled points in this picture. The new voltages should be 1.49V for the GPU and 2.23-2.25V for the RAM.
Multimeter newbies: Switch multimeter to DC Voltage. To measure the voltage for each part, place the red tester lead of your multimeter in the circled "divit." Place the black tester lead anywhere that's ground, like the side of your case. Play around with the voltage wheel (500V, 200V, 20V, 2V) until you get a reading like 1.49V for the GPU or 2.23V for the RAM.
Do this check for the GPU voltage and the RAM voltage. If the GPU voltage is still 1.2V, erase the ink and redo. If the RAM voltage is lower than 2.23V, shade the resistor some more. If the RAM voltage is higher than 2.25V, lightly erase some of the graphite off of the resistor.
AND THAT'S IT
Start overclocking with Rivatuner, Powerstrip, or Coolbits (Coolbits doesn't allow as high frequencies as the other two).
Comments
A better heatsink fan is highly recommended for this voltmod. RAMsinks for the RAM are definitely recommended. ACTIVE COOLING for the RAM is also recommended. RAMsinks don't do much good without airflow...
I noticed that initially the RAM voltage would measure at 2.23V, but after a few minutes of the card being on, the voltage would increase to 2.25V. No big deal.
There are different variations of the GPU voltmod, ranging from connecting different parts of the card with the conductive pen to connecting the leads on a certain IC to soldering whathaveyou. I for one think that the voltmod in my tutorial is the simplest. There are also different versions of the RAM voltmod, most of them involving soldering. The pencil trick is by far the simplest.
The Simple and Concise 7900GT Voltmod Tutorial, webpage-ified, courtesy of keysplayr2003
I know a lot of newbies are looking for a step by step tutorial on how to do their 7900GT voltmods. It seems like wherever you go you have to either trudge through circuit diagrams, 10+ pages of discussion, awful pictures, or chaotic directions to get this information.
Here it is, all in one place. These steps have all been done by me and have been CONFIRMED to work 100%.
NOTE: The RAM vmod and the GPU vmod are completely seperate things. Increasing the voltage on the RAM will allow you ONLY to overclock the RAM higher than on just stock volts. Increasing the voltage on the GPU will allow you to ONLY overclock the GPU higher than on just stock volts. You can certainly choose to just do a single vmod, like the one for the RAM, but you'll only get benefits for the RAM by doing this.
Doing both the GPU and the RAM vmods is basically a double whammy, and lets you overclock both higher than normal.
Disclaimer
Anandtech and I are not responsible for screwups that result from this guide
Tools:
Digital Multimeter - $20 at RadioShack Brick and Mortar stores or $3 at Harbor Freight online or at Harbor Freight B&M locations. If you get the RadioShack multimeter make sure to purchase a 12V battery at the same time because it doesn't come with one. The Harbor Freight one comes with a 9V battery.
Conductive Pen - $13 at RadioShack
Pencil - a regular #2 pencil will work. Mechanical, wooden, it doesn't matter. I used a mechanical pencil.
Acetone (nail polish remover, no additives) or denatured alcohol or at least 70% Isopropyl Alcohol - For use in erasing the conductive ink if you mess up. Both available at Walmart or drug stores. Denatured alcohol is in the paint section.
A new heatsinkfan for the core, and eight BGA ramsinks for the RAM
Picture of the 7900GT so people can get their bearings.
RAM voltmod: (pencil, incredibly easy)
RAM Voltmod Section Blowup
1. Locate the RAM voltmod section on your 7900gt and take out your multimeter. Verify that the resistance across the circled resistor is 608 ohms.
Multimeter newbies: Switch your multimeter to the OHM section and put the red tester lead on the left side of the resistor and the black tester lead on the right side of the resistor, or vice versa. Play around with the OHM switch (200, 2K, 20K, 200K, etc) until you get a reading of 608 on your display.
2. Lightly shade the circled resistor with the pencil, from end to end.
3. Shade or erase until the resistance across this resistor has changed to around 553 ohms (check with multimeter).
GPU voltmod: (conductive pen)
GPU Voltmod Section Blowup
Getting to 1.5V: The 7900GT core comes stock at 1.2V. A regular GTX does 1.4V just fine. 1.5V is also fine.
1. Take your conductive pen and carefully trace the red lines in the above picture. It's best to trace a few practice lines on paper to get a feel for the pen's ink flow. It's harder than it looks if you do it freehand. My lines, if you can even call them that, are definitely not pretty, but they still work. If you want to get straighter, more defined lines, use masking tape to outline where you want the lines to go, and paint over that outline with the pen.
2. If you messed up, use acetone or isopropyl alcohol to dissolve the ink, wipe clean with a Q tip or section of paper towel, and redo.
Getting to 1.4V:
Trace the 1.4V line in this picture.
Getting to 1.55V:
Trace the line in this picture.
Verifying that the Mods Work (testing the voltages)
1. Put your card back into your computer, being careful not to touch the conductive ink or the resistor.
2. Turn your computer on. Measure the GPU voltage and the RAM voltage at the circled points in this picture. The new voltages should be 1.49V for the GPU and 2.23-2.25V for the RAM.
Multimeter newbies: Switch multimeter to DC Voltage. To measure the voltage for each part, place the red tester lead of your multimeter in the circled "divit." Place the black tester lead anywhere that's ground, like the side of your case. Play around with the voltage wheel (500V, 200V, 20V, 2V) until you get a reading like 1.49V for the GPU or 2.23V for the RAM.
Do this check for the GPU voltage and the RAM voltage. If the GPU voltage is still 1.2V, erase the ink and redo. If the RAM voltage is lower than 2.23V, shade the resistor some more. If the RAM voltage is higher than 2.25V, lightly erase some of the graphite off of the resistor.
AND THAT'S IT
Start overclocking with Rivatuner, Powerstrip, or Coolbits (Coolbits doesn't allow as high frequencies as the other two).
Comments
A better heatsink fan is highly recommended for this voltmod. RAMsinks for the RAM are definitely recommended. ACTIVE COOLING for the RAM is also recommended. RAMsinks don't do much good without airflow...
I noticed that initially the RAM voltage would measure at 2.23V, but after a few minutes of the card being on, the voltage would increase to 2.25V. No big deal.
There are different variations of the GPU voltmod, ranging from connecting different parts of the card with the conductive pen to connecting the leads on a certain IC to soldering whathaveyou. I for one think that the voltmod in my tutorial is the simplest. There are also different versions of the RAM voltmod, most of them involving soldering. The pencil trick is by far the simplest.