Radeon X800 Pro/XT/XT PE Voltmods
Tools and Supplies
- Digital Multimeter (a must have to complete mod safely)
- Electrical Tape (get the color that matches your PCB)
- 2b Pencil (works the best, found one at Staples in Drafting Department)
Getting StartedBefore we get down to work, lets run through the multimeter to make sure we're on the same page. You'll be using two different settings. One to check the voltage before and after we make our changes. The second to check the resistance in Ohms of the resistors we're using our 2b pencil on to safely lower their resistance to raise the voltage. To check the voltage for the VCore and VMem starting measurements set the multimeter to DCV 20v and to check Ohm resistance you'll set the meter to Ohms 2k or 20k depending on the resistor we're working with.
I'd like to note that you don't need to do all of the next steps if you're not doing all of the vmods. Try the VCore vmod first then move on to the next one if you feel you need to.
So grab a pencil and paper (should already have a pencil) we're going to write down our starting voltages. Starting with Image 1 locate the green arrow pointing to the capacitor in the top right hand corner labeled C60. Now with the system running and the side cover off visually inspect the area to first locate the capacitor and making sure there isn't anything in the way. Set your meter to DCV 20 V before placing the black lead of your meter on the screw holding in the video card, this is ground. Important when touching card with a meter lead that you don't accidently ground something out. Carefully place the red lead on the top side of capacitor C60 (you're upsidedown from the pic facing the card). Your meter should be reading around 1.39v, cards vary from manufacture to manufacture. Write that VCore number down for future reference. There is not a measure point for the IGPU Vmod that I'm aware of at this time.
For the time being lets move on to the VDD (VMem) measure point. Again in Image 1 locate the green arrow pointing to our measure point, over to the left of the card labeled C213. A closer view in Image 3, it's the top capacitor in the top right hand corner. With the same steps we used in the previous measure point. Place the black lead on ground carefully placing the red lead on left side of C213 (you're upsidedown from the pic facing the card). Your meter should be reading around 2.00v. Write that VMem number down for future reference.
Next measurement we'll check before we start the mod will be VDDQ. Find the measure point in Image 1, green arrow pointing to capacitor C215. Right below the VDD capacitor, closer view in Image 3. Once more with the same steps as before place the black lead on ground carefully placing the red lead on the left side of C215 (you're upsidedown from the pic facing the card). Your meter should be reading around 2.08v. Write your VDDQ number down for, you guessed it, future reference.
Pencil TimeTime to shut down the system and take out the card, your work area should be static free. Yes, at this point you should be reading from a printed document. Basically what we are trying to do is use our 2b pencil to reduce resistance on the selected resistor. You'll need to measure the resistance in Ohms first, by placing the black lead on one side and the red lead on the other side of the resistor, write it down it's our starting Ohm reading. Then gently run your pencil along the side of the resistor from one end to the other. Do a couple swipes then check again with the meter. Using the number you've written down subtract the new reading. For example if your starting Ohm reading is .418k and your new ohm reading is .400k obviously it's a 18k ohm drop in resistance. If you go by the rule of 15k Ohms equals roughly .04 V to .06 Volts. Add the .04 V - .06 V to the reading that you saved for future reference, for example the VCore reading of 1.39 V your voltage should now be around 1.43 V - 1.45 V. A 10k variable resistor will give you around .04 Volts so again that's around 15 Ohms you need to reduce your resistor.
Keep in mind that if you want your card to last awhile don't get greedy.