ATI 4850/4870 voltmod thread

[LuxZg]

kur¡,
Go here.
Look for "VDDC measure" in the pic...

OK, I've got a problem measuring, probably cos of my incompetence, but wanted to recheck with you guys.

I did use the above URL, and picture that is shown there. But I couldn't get any numbers from my multimeter, though it could be that I've missed the point somehow, even though I've tried 5-6x..

So let's take it step by step, as I don't use MM usually, and I've borrowed this one just for the occasion

1) I take multimeter and turn it on
2) I have a switch and a dial to set up the desired range
a) little switch that selects amps/ohms/and two types of voltages. One is V (that's DC right? or not?) and the other is V~ (AC?). I'm not certain which of the two is right (that's why I've included pictures, I hope they are shown right in post), as I'm not sure if GPU voltage is AC or DC.. Though I was just struck with the VDDC markings, but it could mean anything as I still don't know what MVDDQ means either except that it's some memory voltage So I guess it's DC, but tell me anyway, is it this one or this one ?
b) next I have a dial that's similar to this one ; it lets me select 2/20/200 for whatever I've selected on the switch (ohms, amps, volts). Should it be better to select 2V or 20V, since VGPU is <2V actually, I guess 2V is better and more precise, right?
3) I take those black and red umm "cables", and I put one on the VDDC measurement point on the VGA card, and other one where? As much as I know, it's just important that circle is closed, so I've just put the other side on the PC case.. It worked fine when I've tried to measure current on peripheral/molex plugs, showed 5V and 12V no problem.. But if VGPU is DC than what? And I guess than there is difference between using red or black one.. So a bit more info in here as well..

There are few things I could have missed, I'm no longer sure, but maybe I've switched to wrong voltage type (step 2-a). Also, maybe my PC case is not good for closing the circle when measuring VDDC on GPU (step 3), or i've just placed wrong red/black cable on the measurment point. Also, I could have missed the measurment point completely, so I didn't have good enough contact. Anyway, please, step-by-step instructions would be real nice, so I can do some measurments today or tomorrow when I should also have IR thermometer and power consumption meter, so I can check what are the effects of voltage/clock changes in BIOS, and how will it all affect stock cooler vs aftermarket cooler..

Thanks in advance

EDIT:
OK, solved. Not sure what I was doing yesterday, but today it works.

Btw, steps go as followed, just in case someone as confused as me tries later on
1) Take multimeter and turn it on
2a) select part of multimeter which shows
2b) with dial select 2V; in case you use same dial to select range and type, make sure, it says "2"
3) Take the red probe (cable) and put it on "VDDC measure" point marked in picture, while putting black probe to ground (meaning electrical ground, not on the floor -> black wires in molex/peripheral connector should be fine, just stick it into one of the two middle molex holes, so you have black on black, can't go wrong.. unless you're ME )

Interesting enough, I got 1.271V idle on 160/225 clocks, while 1.288V when overclocked to 790/1100 but still in 2D. Under load under overclock I get 1.305V measured. Is this ok? I don't have any mods yet on this card, neither BIOS or hardmods.. I'll go restart, and try again, as I haven't written it down right away..