7900GT over voltage protection?

[***Deimos***]

Meh, I can do 10K with a little overclocking too..

oh wait,
thats 2006, not 2003... -_-
my scores are so low
I hope those next shipments at end of months are more plentiful.

[Greg_1]

what clocks do you have on 1.4V ?

[aicjofs]

I decided to drop a quick bit of window deicer repair kit paint on pins 30 and 31 to ground(pin 32), along with the d511 to ground. Just a touch with the point of a needle. Just for testing at this point.

evga 7900GT @ 695Mhz/1880Mhz (stock 550Mhz/1580hz)

11236 3dmark 05

At stock 1.2v and 550Mhz the voltage reg temp was 49C with contact temp probe at load. At 1.55v and 695mhz the temp got as high as 63C.

Seem a real easy mod. More worried about the voltage regulator burning up then the chip itself. Hitting 44C with CPU and GPU loaded with mid range water. Wonder how robust the voltage regulation is...

[t024484]

I decided to drop a quick bit of window deicer repair kit paint on pins 30 and 31 to ground(pin 32), along with the d511 to ground. Just a touch with the point of a needle. Just for testing at this point.

evga 7900GT @ 695Mhz/1880Mhz (stock 550Mhz/1580hz)

11236 3dmark 05

At stock 1.2v and 550Mhz the voltage reg temp was 49C with contact temp probe at load. At 1.55v and 695mhz the temp got as high as 63C.

Seem a real easy mod. More worried about the voltage regulator burning up then the chip itself. Hitting 44C with CPU and GPU loaded with mid range water. Wonder how robust the voltage regulation is...

Don't worry about the voltage regulator, it is doing nothing else than switching Mosfets on and off.
These mosfets are doing the hard work, and they are well protected by the current limiter.

[tranceaddict]

what clocks do you have on 1.4V ?

I'd like to know as well, since that is the 24/7 voltage I will use with the NV Silencer 5.

[Garrett]

Very interesting thread, :thumbsup: for those helping here

[t024484]

Very interesting thread, :thumbsup: for those helping here, I only missed the part @ what voltage exactly the OCP kicks in... I've read 1.27, 1.28, 1.29...

Maybe you missed the point. OCP is overcurrent protection, and I haven't read sofar of anybody where the OCP "kicked in".
OVP is overvoltage protection, which becomes active when you use a Variable Resistor (VR) to adjust the voltage.
The point is, DO NOT use a VR on this board, but adjust the voltage by shorting pins to ground.
In that case you will never ever experience that there is a OVP guarding your expensive board, it will be working for and not against you.

[Counter CS]

How i can do the same to my 7800GTX 256Mb ?

[Garrett]

Maybe you missed the point. OCP is overcurrent protection, and I haven't read sofar of anybody where the OCP "kicked in".
OVP is overvoltage protection, which becomes active when you use a Variable Resistor (VR) to adjust the voltage.
The point is, DO NOT use a VR on this board, but adjust the voltage by shorting pins to ground.
In that case you will never ever experience that there is a OVP guarding your expensive board, it will be working for and not against you.

Thanks for clearing it up... I'm leaning towards buying the 7900gt, but I'm still "stuck" with a 7800gt meanwhile

[illuminati-hwt]

I vmodded my XFX 7900GT to 1,4v

Stock cooler + two 8x8 fan @ 5v sitting under gfx..

Measured first: 1202mv
After vmod: 1401mv

Used conductive ink and tape. Tape was used to make the conductive ink go where I wanted it to go.. Put tape on pcb, apply ink, remove tape...

I used this image as reference:



This is the result. (picture is upside down...)

Core runs at 644mhz. Warm and stable.
The mod can be undone using alcohol or acetone.. the latter works for sure.

[alpha0ne]

Nice and neat work illuminati-hwt, that picture and explanation make it easy for anyone

[Codeman05]

Thanks for the post, I was a little hesitent to try the other mods...my hands aren't particularly stable with an iron...but I think I can handle this one

I have some left over wire from when I Vmodded my x850...all I need to do is solder it across those points and that is it...as we are just shorting the "gap" correct (can't find conductive ink around here)...I'm sure that is the case, but, I'd be really pissed off it I killed this card doing something stupid hehe


on a side note, has anyone done a Vmem mod? If so, how is the memory scaling with the voltage

I vmodded my XFX 7900GT to 1,4v

Stock cooler + two 8x8 fan @ 5v sitting under gfx..

Measured first: 1202mv
After vmod: 1401mv

Used conductive ink and tape. Tape was used to make the conductive ink go where I wanted it to go.. Put tape on pcb, apply ink, remove tape...

I used this image as reference:


This is the result. (picture is upside down...)

Core runs at 644mhz. Warm and stable.
The mod can be undone using alcohol or acetone.. the latter works for sure.

[Pyr0]

just ordered some conductive silver paint
now i just have to wait for the 7900 to arrive in stock

[SF3D]

Changing volts is so easy now

Attachment 45187

1.5V-->1.7

[Clint]

Changing volts is so easy now

Attachment 45187

1.5V-->1.7

Ahhh, that is just....beautiful!

[tranceaddict]

I vmodded my XFX 7900GT to 1,4v

Stock cooler + two 8x8 fan @ 5v sitting under gfx..

Measured first: 1202mv
After vmod: 1401mv

Used conductive ink and tape. Tape was used to make the conductive ink go where I wanted it to go.. Put tape on pcb, apply ink, remove tape...


Core runs at 644mhz. Warm and stable.
The mod can be undone using alcohol or acetone.. the latter works for sure.

Thank you. Finally an easy explanation which everyone can follow and do. You are the man.

[Garrett]

This conductive ink business... I've got some, and is it possible on the 7800 GT too?

[t024484]

This conductive ink business... I've got some, and is it possible on the 7800 GT too?

No, you will need a resistor.

[***Deimos***]

Its really funny how at first the mods for 7900GT seemed so difficult, but in fact I think they are the easiest and most consistent yet. You dont even need any resistors, and you can select voltages in exact 0.05V..

SF3D.. that dip switch is so beautiful. You can do voltage scaling results SOO EASILY. Would you? (0.1V increments are more than sufficient) Also, does higher Vgpu help memory overclocking?

[majestik]

Changing volts is so easy now

Attachment 45187

1.5V-->1.7

I'l love you long long time if you write a detailed explanation/guide on this!

[aicjofs]

Also, does higher Vgpu help memory overclocking?

I was able to go from 880 to 940 from 2.0 to ~2.2. However the higher you get the core speed the less the memory wants to cooperate. I'd say it helps a little but not a whole lot in my case, but I haven't seen enough feedback to make a statement one way or the other. People are getting some crazy speeds at stock. I swear I was reading the data sheet for Samsung xxxxx(I forget)-BC14 and the default volts were 1.8v, but all these GT's are 2.0v... is it overvolted already?

[Dihon]

Just want to recap the whole thing from the beginning :
1. Do we need to remove any resistors to disable the OCP ??
( In the beginning there's a post about removing & changing the resistor from 3.5K to 150 % higher, then later we read about removing 2 resistors )

2. How about Vmem discussed earlier in this post ?
My card ASUS EN7900GT with Samsung BC14 after lowering the resistor to 560 ohms, I can bench till 1025 MHz.
But I can't measure the Vmem, I don't have a precise digital Volt meter.

[Haltech]

Im going to do this mod when my pen arrives.. for anyone looking for conductive paint and/or pens, this is a pretty good source...

http://www.semsupplies.com/Merchant2...gory_Code=SSAA

[Codeman05]

ok, now I was looking at my card today getting ready to do this mod, and the circular contact point (using the "conductive pen" method)...the left most one in the above pics...does it need to be scratched or uncovered??

On my card it is just a white dot that feels like the rest of the PCB, and dosen't seem like it would be conductive. Do you need to scratch the coating off to get down to the contact?

[aicjofs]

Hmm I don't know. I have an Evga and a XFX sitting hear and both are conductive.

I just randomly picked that spot because it was the closest ground that was easy to access, and everyone could connect without fear of shorting anything else out, so I posted that picture. You can connect to any ground you want.

Best bet is to use a multimeter and ohm it out, but if it's a white dot there is probably something over it. What kind of card is it?

If you don't go nuts it's not going to hurt anything to scrape a little hole and see. Unless you are going for the "remove this mod and no one can tell effect"