VR-Zone

This is a simple guide to some simple pencil mods for your Radeon 9800 XT. All you need for this job is a pencil (2B prefered), an eraser, a multimeter and some guts.

First you should measure your stock core voltage. Measure it from this small contact spot with the red tip of your multimeter.

Red tip to spot and black tip to grounded spot like your video card handle.

You'd have to measure it while the PC is running so be careful. It usually measures around 1.77v. For this card, it measures 1.77v.

Next, turn off the PC and take out your card. Focus your attention toward area marked with green circle.

Look for the resistor marked R1597.

Measure the resistance across the resistor with your multimeter.

It should read around 342 ohms. Mark down the default resistance. Now you can start to pencil it.

Pencil it in such a way.

After each smooth stroke, measure the resistance across the resistor. Add 1 stroke on top of another to lower the resistance more and more. I would go in 15 ohms steps. Dropping the resistance from 342 ohms to 327 ohms, my core voltage increases from 1.77v to 1.81v. So, roughly, a 15 ohms drop will increase voltage by 0.04v. Thus, I would reduce resistance by 15 ohms, then run the card to see the increase in voltage, repeatedly until I reach the voltage I'm satisfied with. Do remember to check the resistance before running the card to ensure you don't drop the resistance too much. When done, paste a tape over the mod spot so that the graphite doesn't get blown off.

With very good aircooling, 1.9v should be fine. With better cooling, 2v or above is feasible. When you go above 2v and run it overclocked high, you may trigger the over-current protection when your card draws too much power and our PC goes into blank screen mode. You will need to do the over-current protection mod, which can be done with a pencil as well.

Look for R1596.

Measure it with your meter. It should read around 40K ohms. Just pencil it to around 20K ohms the same way. This should solve the over-current problem. When done, paste a tape over the mod spot so that the graphite doesn't get blown off.

So that's it. For Voltage mods basics and guide, you can refer to

this