TheSubtleKnife

For those of you who own a shiny new 8800GTS, or the slightly less shiny 8800GT, and that 750core/1800shader just isn't cutting it for you, but you are afraid to take a soldering iron to your card for fear of fubaring your card, or voiding your warranty, I have devised a completely reversible voltmod for the G92 cards. Note: The basic Vmodding directions are not mine (I just elaborate on them a bit more), I got them from Guru3D: http://forums.guru3d.com/showthread.php?t=247576

Neither OCN or I will be responsible for any damage caused by following this guide!!

Materials:
1k Ohm 15 turn VR http://www.radioshack.com/product/in...tId=2062307&cp
2 thin wires
Electrical tape
Scissors
Super glue
Isopropyl alcohol + Q tips
Multimeter



We will be working on the end of the card, near the 6 pin power connection ( These pictures are taken after I did the mod, but I will undo the mod as much I can so I can show the steps in the pictures)




First off, wire up the VR correctly. If you are using the Radio Shack VR, the middle pin is going to be connected to ground, and the back pin (the one farthest from the knob) is going to be connected to the Vgpu “solder” point.
Before you install the VR, check to make sure you know what direction you need to turn the knob to raise and lower the resistance. You should have it adjusted to about 300-400 ohms before you proceed.
Glue it down onto the PCB, near the power connection.




Here is a closer up picture of where we are working on.


(image courtesy of 3Dguru)

Since all the red dots are connected electrically, it doesn't matter which one or how many you connect to. Clean the area with alcohol, so the electrical tape will stick better.



Then procede to tape around everywhere around the red dots, to avoid making unwanted connections, and risking shorting your card.



Then, strip the wire coming from the end pin on the VR to about 1/8” at the most. Curl the metal leads so it has some thickness, then place the tip onto the connections that you left bare.



Tape over the tip to hold the wire and keep the connection. Tape where ever else you feel necessary to keep the wire in place. Yay, hard part done!


Now, to connect the middle pin of the VR to ground. There are a ton of grounding points on the card, but the one that is easiest are the screws that hold on the HSF. You don't even need to tape this one down. Simply take off one of the screws, put the ground wire(stripped to about 1/8-1/6”) so it is touching the bare copper where the screw is supposed to be, then replace the screw so it holds the ground wire.





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 around 400-500 Ohms, you should get a reading near 15 Ohms.



If you still get a reading that is 400-500 Ohms, recheck your connections. That confused me, but what is happening is that the resistance from the Vgpu point to ground is originally 15Ohms, and you are simply hooking up the VR to run in parallel. This page may help explain it better: http://www.1728.com/resistrs.htm (try putting values of 15 and 500 and then 15 and 400 or 300) If you are getting the correct readings, its time to see if the mod works.


Put your card back into your mobo, and get ready to measure the voltage. You can do this by shoving the – lead of your multimeter into a black (ground) molex fitting, they usually make a perfect fit.



Take the + lead and touch any of these pads to measure the volts. Power up your comp, and take a voltage reading.



If you have the VR set to 300 or something, you should see a slight increase in volts( about 1.20 is what I got). If you got this far, congratulations! Your voltmod is sucessful!



To increase the voltage farther, just turn the VR to a lower resistance ( Be sure to measure the volts constantly, as to avoid overvoltage). Use your head when messing with the volts, dont be like “ZOMG VOLTMOD YAI!!!” and crank it up to 1.5v.

GOOD LUCK OVERCLOCKING!!!!


My Overclock before:

I'll have pics of proof here in a little bit

1.1v
756Mhz core
1836Mhz shader

After:
1.25v
800Mhz core
2000Mhz shader



Validation http://www.techpowerup.com/gpuz/9346g/

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Refresh

I would try this if I had an XFX card

Semper Fidelis

XFX wouldnt cover that, they just cover overclocking and aftermarket HSF installation.

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TheSubtleKnife

why? if you bork it, take the tape off, unglue the VR and send it back! =P

screenshots coming soon..dont worry

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reberto

They cover volt mods too

sledgehammer1990

I actually did a vMod on my GTS G92 a few days ago. It turned out great with no problems.

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bluedevil

I am tempted to, but then again hardwiring anything on a GFX card scares me.

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sledgehammer1990

I know, It scared me at first, but it was actually pretty easy after getting the right tools. I got the thinnest solder I could find, .022" It help a lot.

Just make sure you do your research and ask questions. That is what forums are for.

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TheSubtleKnife

updated with a screenshot and a validation...

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Semper Fidelis

Button stealer...

__________________
Get Custom Avatars Here | Wallpapers Here | Brown Flow | CM690 Club | OCN Pixel Wall | Ballistix Club

"Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke
Aumotocnic: An unfortunate member of the overclock.net insomnia club.
Overclock.net Headphone Club: Because perfect hair is overrated.