9800GTX voltmod thread

[K404]

Whos got one?

Please post up high-detail pics of the rear of the card and lets get things moving

[largon]

vGPU mod is almost identical to G92GT/GTS.


GDDR3 vDD (vMEM) + vDDQ are a bit trickier as they are controlled by the same 3-way buck controller. The problem is I can't tell which regulator feedback pin is for vDD and which for vDDQ just by looking at the pics as I don't have the card...
:|


First, I would need someone to measure the output voltages of those Delta HAHE1040 chokes on the front side. One should be ~2.00v, the other under 1.5v.

[kontrazeus]

hopefully I can find a 500k so i can test it on mine!

do you think a 1k will work on this card as well?

[K404]

*if* 500 Ohm is fine, 1K ohm will be fine too, but you will have a little less accuracy with voltage setting.

[largon]

K404,
What's with the "if"?
I did have the necessary measurements at hand before scribbling the "500Ω" into the pic...

[K404]

Sorry- I was responding to the "preliminary"

absolutely no offence meant

[SergeRY]

Works no problem, indeed just like the 8800gts g92 due to the same primarion controller chip. used a 1k tuned down initially to 500 ohm. I was in a hurry and didn't measure the resistance at the end. @ 1.389 idle, was good for 891/2228/1235. Tried up to 1.45 idle - 900 MHz core is still not stable under water. I need to try a remount of my blocks though (swiftech mcw-60), I forgot to clean the old TIM off it was late.

My pictures of the mod are camera-phone terrible. if anyone wans torture I can upload .

@largon, delta chokes read 2.02V top, and 2.10V bottom. hope this helps, I can take any other readings tonight if you need them also, the components to the right of the prim' chip look a little different... thinking towards ocp, any ideas?

here a quick 3dmark, 115 pcie. stock ram, mild overclock otherwise.
Edit: oops, got cut off. ram @800MHz, 790i Ultra

[largon]

SergeRY
Those voltages make perfect sense, thanks.
Dunno what I was thinking when I said the other (vDDQ) should be <1.5v...
@ me

I doubt there's need for an OCP mod as the GTS with *just* 3 phases doesn't need it even at 900/2400/DDR-2200, those 4 phases on GTX should be enough for pretty much anything.


K404,
Heh, I was just kidding.

[SergeRY]

Originally Posted by largon

SergeRY
Those voltages make perfect sense, thanks.
Dunno what I was thinking when I said the other (vDDQ) should be <1.5v...
@ me

I doubt there's need for an OCP mod ...

np, glad to help. not TOO far off

as far as ocp: I set vgpu while at bios screen to 1.4(?) it jumped to 1.505 idle in windows. this was enough for extreme instability. crashing withing 5 seconds of rivatuner. so there may still be a need if higher voltages are needed. Dunno though, maybe the 4th phase will make it unnecessary when going to colder temps (enough voltage to get really crazy without ocp removed).

just my thoughts
-serge

[cole2109]

For 24/7 910/2220/1260
1.38V






I still testing for benchmark...

[K404]

is the 1.38V for idle or load?

910MHz is nice!

[kontrazeus]

where are the measuring points on the card?

[I34z1k]

Doesn't seem worth it to me I can bench @ 865 anyway?

[Ertu]

Originally Posted by kontrazeus

where are the measuring points on the card?

Hy everyone, same question here where can we read the GPU voltage ??

thxs

[cole2109]

Originally Posted by kontrazeus

where are the measuring points on the card?

[SergeRY]

Originally Posted by cole2109

lol, thanks, my photo capabilities are severely limited

Originally Posted by SergeRY

also, the components to the right of the prim' chip look a little different... thinking towards ocp, any ideas?

Originally Posted by largon

4 phases on GTX s

of course, 4 phases = 4 resistors needed, im an idiot anyone point me in the direction of figuring out the values?

improved 3dmark:
http://www.xtremesystems.org/forums/...1&d=1207521394

[mieller]

hi guys just wondering what waterblocks fit the 9800GTX?

[SergeRY]

Originally Posted by mieller

hi guys just wondering what waterblocks fit the 9800GTX?

most. swiftech mcw-60, dtek I'm sure, and many others.
here is a photo of my vmod, complete with easy disconnect on ground.

[Ertu]

when i read voltage at idle and load
i can read 1.21v and 1.228v

is this correct ??
I can see here than you put these setting at 1.38v

[Ertu]

i think there is something wrong
i read from other resistanse 1.235 v

what's wrong with this value and where is exactly the measuring point
before i solder anything

[SergeRY]

Originally Posted by cole2109

Originally Posted by Ertu

when i read voltage at idle and load
i can read 1.21v and 1.228v

is this correct ??
I can see here than you put these setting at 1.38v

I read 1.208V idle from the first resistor(?) to the top left of the GPU(backside of card, see pic). I measure from the right side of the resistor.

Originally Posted by Ertu

i think there is something wrong
i read from other resistanse 1.235 v

what's wrong with this value and where is exactly the measuring point
before i solder anything

not sure why that is, other than a load, the voltage is the same for me. measure from the same point, and with the same ground every time.

[largon]

Would someone be kind enough to measure resistance from the marked pads to ground on this pic:

[Spacemaster]

How to read VGPU voltage for this babe?

[largon]

^
See post #15.

[n3wbi3]

ok gonna volt mod my 9800gtx's, iv never volt modded b4 but this thread is helping, can somebody plz post some more pics....
This correct guys?