9800XT Vgpu mod

[EmineM]

im using an unmodded Mach II

The center pin definatly goes to the PCB of the graficscard pin 1 or 3 then go to GND... on which end of the transistor should I solder the middle pin to? for vgpu mod

[Tyberius]

Okay, for the vgpu mod, this is the best info i can give you, i assume you already know the area in which you have to do the mod...so heres a drawing i did.

[EmineM]

Perfect =) that clears up everything mate

Charlie did it differently tho he soldered Ground to R1592 I think

[EmineM]

Damn cant add a pic to a already posted thread...
heres the pic of charlie
anyway I will do it your way tyberius thanks for the info

[Tyberius]

yeah, i dunno about that one, i suppose it'll work, but im fully comfortable soldering on SMD resisters, so i dont care, i know the way i did it worked beautifully, only thing that got complicated was Vmodding my Asus 9800xt, had a slightly different layout than my BBA, no vgpu read point...but my man Catch22@Play helped me out with that one

[EmineM]

well I did both mods sucessfully..
VGPU is at 1.9 and VMEM is at 2.95
but theres basically no overclocking difference then without the mods...
Before I was able to get 526.5/ 425 on my Mach II ST Mounted on the GPU now
with the mods I am able to get 526.5 / 440

Both readings are accurate.. mods were done correctly and with success the reading points show Vgpu 1.9 and vmem 2.95 so it works but at 3dmark01 Im getting heavy artifacts at 534/430
with the same card a guy got 610 / 440 out of it using vmods and an Mach II
according to rivatuner the card is around 0 °C so I do not think temperature is a great problem.. my multimeter says that the core has -10 °C or so...

[Tyberius]

Well, you didnt really raise up the voltages all that high from stock. I have an engineering sample ATi 9800xt and the stock vgpu was 1.85v and the mem was 2.85. I run my vgpu at 2v and my memory at 3.0v even, and im just liquid cooling the gpu and active cooling the ramsinks. Backside of GPU isnt even warm to the touch. Helped greatly for me, both the added cooling and the vmods that is...dont know what one helped more as I did both almost at the same time. 535gpu/420 ram. What are you using to cool your ram????? I went overboard on RAM cooling and I cant get that high, yet. Check it, this was my card before my vmods. PS: you sure your ram clock being that high isnt whats causing your artifacts?

[EmineM]

rofl sick man I was able to hit 585 / 438 today..

[Tyberius]

VERY NICE! What'd you change? Increase the vgpu voltage I'd suppose?

[EmineM]

well Like I said the vmem wasnt working quiet well , I expected too much at lower voltages which made me drop back a bit..
So I unsoldered the vmem mod and just did the GPU I was able to hit 27.5 k with 2v on GPU
I then increased to 2,05 on GPU and redid vmem mod and im running 3.25 without 3,3rail mod I love my PSU and was able to get 438 MEM

With the rail mod I assume I would get further, right now im on 27,9 k in 3dmark01

[Tyberius]

Ummm....I hate you.....j/k Wow impressive, I guess I shouldnt complain, 25k on a koolance liquid cooling system isnt bad

[T07N]

Where did you get those little fans?

[Tyberius]

Ummm, I dont remember exactly, just google 20mm fans, you should find em. They were only $4 each, but last time I checked they were all sold out.

[Boyne7]

i just did this mod and when i measure the voltage with the mod off (i have on off switch) it gives 1.41v, when i measure voltage with mod on resistor set to 10k ohm, it gives 1.47. are these values correct. or do i substitute them for the 1.4 in the equation Vgpu=1.4x(1+432/1620)=1.77V to get my actual vgpu?

[Boyne7]

ok wtf... without the mods i could get 470core with the mod i cant even run stock XT speeds without artifacts
looks kinda like what VoRtAn_MaDgE was getting, but my artifacts dont go away when i turn on the vgpu, they actually get worse. whatd i do wrong (also i modded the card the way tyberius posted)
Ok i just tried upping the voltage and now it reads 1.5v and the white dots went away at stock speeds, but if i try to overclock at all it artifacts like mad

[Boyne7]

i just upped it even further so it reads 1.58v, i dont think it did hardly anything to the oc, actually it helps minutely. but still i cant overclock anywhere near what i could before the mod.

[Boyne7]

i think i figured it out. it WAS actually running at 1.4v originally i must have accidentally unsoldered that one resistor. i upped the resistance till it read 1.8v and now it works just like it originally did. strange but it seems to work.

[VoRtAn_MaDgE]

Remake the gpu mod buddy...
Something is wrong there...
i had the same problem but fine now.

[Boyne7]

well i upped the vgpu to 2.0v and now i can go 500core with no artifacts. i think its working, but i think its just that little resistor must not be connected on both sides causing the stock voltage to be really low. now i worry though, if that were to just touch randomly sometime itd fry my card. so i think im gonna take it out a fix that, then it should be good.

[Byron]

Hi guys, tried that mod on a Asus 9800xt VIVO and it totaly got f**cked! I'm trying to see whats going on but both R1591 and R1592 are same Ohms!

I removed the mod, same thing...

System doesn't boot... mobo/drives are running normaly but nothing else.

Plz any help really appreciated,
Cheers,
Byron

[Byron]

Forget it, a mosfet on the card just went caboom!,
R.I.P.

[KODE]

More pics of Vgpu mod below, good close up (mine):

http://xtremesystems.org/forums/show...highlight=KODE