8800GT voltage mods

[largon]

This guide applies only to G92 based nVIDIA 8800GS, GT, GTS and 9600GSO reference boards. If your card has different layout feel free to report here, and, if possible post clear pictures of the card.


http://www.xtremesystems.org/forums/...1&d=1196804211
Higher resolution image @ Imageshack:

Addendum:
- stock vGPU voltages for this card are 1.05v (2D idle) and 1.15v (3D load)
- stock vMEM voltage for Qimonda GDDR3 (HYB18H512321BF-10) is 2.0v ±5%
- vMEM mod has been deemed almost useless as Qimonda GDDR3 does not OC any better at higher voltages
- 1kΩ variable resistor can be used for the vGPU mod in order to maintain minimum voltage close to stock. 500Ω VR will be more accurate to tune but it will also force vGPU slightly higher than stock even when the VR is tuned for lowest vGPU = maximum resistance.
- vGPU pencil mod turned out to be virtually impossible
- usage of a multimeter is required for tracking the vGPU
- ENJOY!

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Complete GeForce 8800 GS/GT/GTS Voltmods for reference PCB @ techPowerUp!

[metro.cl]

will help when i get home, i'm looking for a vmod becuase that is the limiting factor on my overclock

[largon]

Btw, here are some easily accessible vGPU measuring points:

[HousERaT]

Pencil mod anyone if it's possible?

[nordicpc]

I can't wait to see this fall out. I'll have one on Thursday, and am anxious to void some warranties with a VF-900.

[kiwi]

Originally Posted by HousERaT

Pencil mod anyone if it's possible?

Only vmem

[largon]

Yup, vMEM is definitely pencil modable and actually, vGPU should be too if you're careful [EDIT: VGPU PENCIL MOD UNTESTED! DO NOT APPLY!]). BUT a multimeter is a MUST for a safe vGPU pencil mod... The resistor is awfully tiny but it is doable, it's possible because the affected resistor has higher resistance than on G80GTS/GTX thus pencilling is easier.

The modable resistor for vGPU is the one marked with numbers 2 and 4, but I need measuments of the requested points to be able to calculate the target values for VRs / pencil resistance.
EDIT: VGPU PENCIL MOD UNTESTED! DO NOT APPLY!

For vMEM I need the measurements for spot7-to-spot8/ground in the second pic.

Would someone bother measuring the stock vGPU?
Measuring points can be found in post#3.

[HousERaT]

/subscribed

[metro.cl]

Between 7 & 8 is 612
Between 2 and 4 is 011
Between 2 and ground is 015

1 to 2 = 002
1 to 3 = 002
7 to ground = 002

vGPU 1.06v

[dinos22]

here are all the other photos i posted there




here is an actual image of my card here

Originally Posted by largon

Thanks, dinos22.
Need clarification on the existence of certain traces and few resistance measurements, see attachements.

First pic:
There should be traces between points 1, 2 and 3. It certainly does look like there is a trace between 2 and 3, but is there one between 1 and 2? = if there are traces between 1, 2 and 3 then resistance between each is ~4-6Ω.
Also,
Resistance between points 2 and 4? (might be <10Ω)

Second pic:
Resistance between points 5 and 6? (might be around 500Ω)

if i set 200 on dial i get 10.4 on points 2 & 4
if i set 20K on dial i get 1.10 on points 5 & 6

looks like my battery might be going on the DMM

best view i can get with camera
naked eye won't work just can't see that

[metro.cl]

point 5 & 6? i get similar reading with you Dino just a couple of 0X of diference

[dinos22]

Originally Posted by dinos22

if i set 200 on dial i get 10.4 on points 2 & 4
if i set 20K on dial i get 1.10 on points 5 & 6

so how do you read this as actual values
can someone tell me

would it be 10.4*200=2080Ω or 2.08kΩ
1.10*20K=22000Ω or 22kΩ

[largon]

Thanks metro.cl and dinos22!

Between 2 and 4 is 011
Between 2 and ground is 015

I'm suprised to hear these points measure that low values. Gonna have to have another look at the vGPU resistor network...
Everything else is like I expected. Especially the vGPU... Lot's of headroom to crank it up, the chip should take 1.4V with ease. :P

Originally Posted by metro.cl

point 5 & 6? i get similar reading with you Dino just a couple of 0X of diference

Points 5 & 6 were discarded because that particular resistor wasn't in the end that very interesting.

Originally Posted by dinos22

so how do you read this as actual values
can someone tell me

would it be 10.4*200=2080Ω or 2.08kΩ
1.10*20K=22000Ω or 22kΩ

10.4 @ 200 dial = 10.4Ω
1.10 @ 20K dial = 1.10kΩ = 1100Ω
The dial selects the maximum measureable resistance. If the result is higher than the selected dial option then the device will simply display "1". So, in a way, one has to know approximately how much the measurement's result should be in order to accurately measure resistance.




Oh, and here is the vMEM mod & vMEM measuring points (stock vMEM is 1.8v ±5%):

[metro.cl]

Originally Posted by largon

Thanks metro.cl!
I'm suprised to hear these points measure that low values. Gonna have to have another look at the vGPU resistor network...
Everything else is like I expected. Especially the vGPU... Lot's of headroom to crank it up, the chip should take 1.4V with ease. :P10.4 @ 200 dial = 10.4Ω
1.10 @ 20K dial = 1.10kΩ = 1100Ω
The dial selects the maximum measureable resistance. If the result is higher than the selected dial option then the device will simply display "1". So, in a way, one has to know approximately how much the measurement's result should be in order to accurately measure resistance.




Oh, and here is the vMEM mod & vMEM measuring points (stock vMEM is 1.8v ±5%):

any way to pencil mod it? i dont have VR here

[dinos22]

Originally Posted by largon

interesting. 10.4 @ 200 dial = 10.4Ω
1.10 @ 20K dial = 1.10kΩ = 1100Ω
The dial selects the maximum measureable resistance. If the result is higher than the selected dial option then the device will simply display "1". So, in a way, one has to know approximately how much the measurement's result should be in order to accurately measure resistance.

i get it now thanks buddy

[largon]

metro.cl,
Sure, just apply a little pencil over the resistor and measure the resulting resistance & vMEM after every application. I don't know how well Qimonda GDDR3 responds to voltage, so, just to be safe make sure you keep the resistance over 530Ω. This way the vMEM doesn't go above 2.0V

[largon]

How about the resistance between these 2 points?
Still about 11Ω?

edit:
It's 00:23 AM over here... And I'm recovering from a nasty flu.
I'm gonna hit the bed.
¦o

[wittekakker]

VGPU in BIOS is set to 1,05V. I saw 1,1V is the highest possible value, maybe it works and boosts your overclock 2%

Made modbios via Nibitor, here is the zipfile, use at own risk.

[K404]

The Primarion datasheet is still essentially private

From other cards that use it, does anyone know what pin is the feedback line?

I wanna test the guide on VR-Zone: find feedback pin, measure the resistance between the FB pin and ground. Multiply this value by 20, and get a VR with the resultant value. Solder between FB pin and ground....seems too easy!

There are VMax and Temp-sens pins as well, so might need to find a way of adjusting VID in due time if the limits are too tight

[oohms]

If someone had a datasheet figuring out an OVP mod wouldnt be too hard... It might even be possible to add the missing phase

edit: Why are the datasheets private anyway? I dont get it

[dinos22]

guys nvidia will not release the info on those
i already tried with all my guys

[oohms]

I think anyone with a "corporate email account" can get access to the datasheet.. You just have to register here:

http://www.primarion.com/Primarion/RegisterAccount.aspx

(I have no idea what distinguishes corporate email from other email addresses )

I also found this:
http://www.primarion.com/PrimarionMa...s/PDB-3544.pdf

That should at least give us some clues. Only the pin numbers are missing, but with a bit of tracing it shouldnt be too difficult to find them.

[oohms]

Heres an attempt at finding the differences between the working phases and the missing one:



If anyone has a pic to this level of detail of the front of this section i can have a look at it too


edit: From looking at their features list, im not 100% sure its as easy as soldering in the components.

-Multiphase power conversion 1-4 phases
-2-bit VID input for additional voltage control
-Driver detect prior to soft-start disables unpopulated phases
-Autonomous or user controlled phase dropping based on current balance and 12V supply faults

[oohms]

Resistor for OVP mod:



This thread by hipro5 will tell you more:
http://www.xtremesystems.org/forums/...d.php?t=162124

[oohms]

MIGHT be the vcore solder point:



(Got info from http://xtreview.com/review164.htm )

Dinos22: What is the resistance between point 1 and ground?

Gawd this is so much more fun than studying for exams