8800s OVP Mod ......

[Mysterfix]

2.52

we need the ovp for 8800GT

people are reporting OVP kicking in at 1.3v which is only good for 1GHz on core with dice (lol ONLY haha)

Yeah, i'd like to at least go 1.35v for some 900mhz action on water.

[T_M]

Yeah lol, i turned off pretty quick

In addition to that, I almost burnt the card last night, straight after writing a drunken post on i4 i started playing with the volts, not realising my probe was in the vCore (CPU) read not vGPU. Kept turning and wondering why my volts werent budging.
Next thing i smelt an aweful burning smell and i pretty quickly realised what was happening. Dont know what i had turned teh volts up to, but the card seems to have survived.

[dinos22]

Yeah lol, i turned off pretty quick

In addition to that, I almost burnt the card last night, straight after writing a drunken post on i4 i started playing with the volts, not realising my probe was in the vCore (CPU) read not vGPU. Kept turning and wondering why my volts werent budging.
Next thing i smelt an aweful burning smell and i pretty quickly realised what was happening. Dont know what i had turned teh volts up to, but the card seems to have survived.

that is amazing

what cooling was on it

[T_M]

Almost empty DICE (with no acetone) at about 0C.
I was idling waiting for LN2 on CPU to pull down.

[dinos22]

lucky it wasn't air cooled

how the heck did it survive such a spike
WOW MAN

you just gave hipro ideas i think
watches him bench at 1.8V now

[T_M]

Given the burning smell, i'd say at least something was damaged.
Maybe i burned a phase of the power supply circuit?
But teh card still runs, havent benched it though.

[Hazaro]

Bump for more details/confirmation/numbers on the GT OVP mod.

[Hazaro]

http://www.xtremesystems.org/forums/...&postcount=276

I set the OVP resistance stepwise down to 2,7k.
At 3,6k the GPU core droped down from 1,3V to 1,05V idle without changing the GPU core resistance .
After setting 1,3V GPU core like before, it still shuts off.
I turned the OVP resistance down to 2,7k and the core voltage droped down to 0,95V.
Set it again to 1,3V and got still a shut off.


I think we are wrong with this resistor for the OVP mod.
We need that ..... datasheet.

Anymore info from anyone, or has everyone just gone into the main thread?

[Alexxx650]

http://www.xtremesystems.org/forums/...&postcount=276



Anymore info from anyone, or has everyone just gone into the main thread?

+1 my OVP Mod not work on my 8800Ulrta Help.
and BIG Vdoop - 0.095

[T_M]

Alex, does your resistance across the OVP resistor read constant value? Or always changing?

[hipro5]

Ohhhh.......C'mon you guys.......!...... .....Who's gonna solder extra coils in parallel with the existing ones so to avoid the BIG Vdroop of it and then test it in real?.....
ONLY thing you need, is to unsolder some coils from an old motherboard and then solder them onto the VGA with a lot of heatage on the soldering iron.....

[Alexxx650]

hipro5 The purchase of the coil also I shall try to make this mod.
Get some .68uH at 25A+ each (at 25*C)..... This you can be put?

[hipro5]

hipro5 The purchase of the coil also I shall try to make this mod.
Get some .68uH at 25A+ each (at 25*C)..... This you can be put?

Yes.......ALSO if you don't mind, solder a couple of electolytic capacitors in parallel with the ceramic ones.....2200uF/6.3V whould be fine....

[T_M]

hipro, i'll give it a go.
Can i use the caps and R47 coils from a P5B Deluxe?

http://www.pcinlife.com/article_phot...p_1.03g-01.jpg

onto

http://www.ixbt.com/video3/images/re...scan-front.jpg

[hipro5]

hipro, i'll give it a go.
Can i use the caps and R47 coils from a P5B Deluxe?

http://www.pcinlife.com/article_phot...p_1.03g-01.jpg

onto

http://www.ixbt.com/video3/images/re...scan-front.jpg

Links don't work......

Yes you could use them.....

[Alexxx650]

Yes.......ALSO if you don't mind, solder a couple of electolytic capacitors in parallel with the ceramic ones.....2200uF/6.3V whould be fine....

Many thanks for answers and your help.


water

[T_M]

For anyone interested in performing hipro's vGPU smoothing mods, here's a confirmed correct diagram of how to achieve it



The caps need to be electrolytic 1500, 2200 or 3300 uF with the '-' terminal on the ground side of the SMD cap, and the '+' terminal on the vGPU side.

The coils should be from an old mobo and just soldered across the existing ones.

[hipro5]

Thanks T_M for the help......

[wittekakker]

Tried the caps couple weeks ago, not of great use, no better overclock or higher benchable voltage. It's the coil that needs a mod. 'Any coil' will not help, you need right value's.

[T_M]

Darn, and i was about to do the mods with 'any values'.
So, what do i need?

[hipro5]

Darn, and i was about to do the mods with 'any values'.
So, what do i need?

'any values' from 0.47uH to 0.82uH...You can put even a 1uH.....

[T_M]

Hmmm, i went to an electronics shop and they had a box full of unlabelled ones.
So i just grabbed a handful of them and a handful of 2200uF 6.3V electrolytics.

Is it the size that determines the value? If so from a photo could you say if OK or not?

[7499richard]

going to do this now that there is a picture!!!

GREAT JOB GUYS!

[dinos22]

T_M what will those mods achieve for you

[T_M]

Higher GPU clocks