8800GT voltage mods

[Masure]

What resistor value is needed to get 1.3vGPU ?

[Renegade5399]

I will make a deal with you send me your bios and the equally write out the settings you want, just core speed, mem speed and what voltage you need. I will mod your bios with these new setting and i will asure you they will work like a charm.

I modded a BFG 8800 GT 740mhz core, 1835 shader and 1000mhz mem at 1.3v and i don´t want to push it further becos. the card don´t belong to me(father inlaw).

Please verify this with a meter before you go claiming this works. Especially considering that at 1.3v I can hit 850MHz on the core. 740 is about average for stock volts.

Did you measure the voltage with a DMM ? Could we know how you do that ?

Maybe you can put the explanation in the 8800 GT bios mod thread as it would be more its place : http://www.xtremesystems.org/forums/...61#post2807561

I would be interested to know how you did since some people already tried without success ... even mavke, the developer of nibitor.

QFT.


OK on another note, the OCP mod was a great success! I used 1/4 watt 2.2kohm resistors from Radio Shack. I soldered wire leads to them and soldered the leads to the caps in question. It's not pretty, but it got the resistors out of the way. I will snap some pics tomorrow night. Now for the results! I finally hit that mystical 900MHz on the core. The voltage is set to 1.45v at load. It sits at about 1.397v idle. Load temp never breaks 34°C under the MAZE4.



Thanks to everyone (especially largon) for all the tips!

[jason4207]

I will make a deal with you send me your bios and the equally write out the settings you want, just core speed, mem speed and what voltage you need. I will mod your bios with these new setting and i will asure you they will work like a charm.

I modded a BFG 8800 GT 740mhz core, 1835 shader and 1000mhz mem at 1.3v and i don´t want to push it further becos. the card don´t belong to me(father inlaw).

I and several others have tried this. All your doing is changing the VID label. You are not changing the actual VID. VID03 = 1.1v no matter what you change the label to.

740/1835/1000 is a typical OC w/ the 1.1v BIOS mod.

There is no VID04 or higher as this would be the only way to go higher. I have even tried modifying the BIOS to add in VID04, VID05, etc. There is room in the code to add these values, but the problem still exists b/c the chip doesn't recognize anything above VID03.

[Kabauterman]

Hey guys,

I do the OCP mod for my 8800 GT 512 MB Rev design
i don't have fixed resistors so I use 2 25kohm VRs and aetup them to 4 kOhm.



Is that a problem or will it works to?

vGPU is a 500 ohm vr.

I hope I have done all what I need to clock my GPU higher :-)
without voltage limitations

[Renegade5399]

Hey guys,

I do the OCP mod for my 8800 GT 512 MB Rev design
i don't have fixed resistors so I use 2 25kohm VRs and aetup them to 4 kOhm.



Is that a problem or will it works to?

vGPU is a 500 ohm vr.

I hope I have done all what I need to clock my GPU higher :-)
without voltage limitations

Very clean job there. I see people like that back corner for the vGPU pot. Using the variables on the OCP mod is fine and actually may be a benefit to you. I used fixed 2.2kohm resistors on my OCP mod. Not to mention mine does not look nearly as neat and tidy as yours. You will be able to clock just fine! Now get to it!

[Shocker003]

I and several others have tried this. All your doing is changing the VID label. You are not changing the actual VID. VID03 = 1.1v no matter what you change the label to.

740/1835/1000 is a typical OC w/ the 1.1v BIOS mod.

There is no VID04 or higher as this would be the only way to go higher. I have even tried modifying the BIOS to add in VID04, VID05, etc. There is room in the code to add these values, but the problem still exists b/c the chip doesn't recognize anything above VID03.

Well i didn´t check the volts with any voltimeter, but here is a screen shot of what i did with the bios and like i said eariler this card is not mine. I could have tested more with it if i had the chance.

Meanwhile i can increase the core to 850mhz but it´s pointless, like i said eariler i don´t own a 8800GT

[Ceph]

Just do OCP,OVP hit the card only at 1.7v as far as I know

I did the OCP mod and it works bekause i can run the end of the Aquamark with 1,4V Load but all volts over 1,20 doesnot work and crysis will freez no matter which clock is set.

[aoch88]

I'm thinking of getting a Galaxy 8800GT and I get to know the vGPU mod needs 500 ohm VR. Now, do I set it at 500ohm and reducing it would give higher voltage or it's the other way round?

[quake6]

I did the OCP mod and it works bekause i can run the end of the Aquamark with 1,4V Load but all volts over 1,20 doesnt work and crysis will freez no matter which clock is set.

Maybe you didnt do right...

I'm thinking of getting a Galaxy 8800GT and I get to know the vGPU mod needs 500 ohm VR. Now, do I set it at 500ohm and reducing it would give higher voltage or it's the other way round?

With 520ohm is about 1.15v as far as I remember

[aoch88]

Thanks quake6 I'll set it around +/- 500ohm for a start. Btw, I shall put the red measuring point on my multimeter to the vGPU measuring point then the black one anywhere on my casing?

How much will 330ohm give?

[largon]

I shall put the red measuring point on my multimeter to the vGPU measuring point then the black one anywhere on my casing?

That is correct, you might want to stuff the black probe into a ground of an unused molex connector. Better contact there.

How much will 330ohm give?

Probably nothing noticeable - but it's really better to start from 500Ω and tune down.

[quake6]

Dont know,didnt measure... Put multimeter red wire on red measuring point and black wire anywhere to ground (example molex connector)

EDIT: Largon is just too fast

[aoch88]

Thanks all What's the default vGPU and vMem? I searched through my bag of VR's and resistor and have a 1K VR which I can use for vGPU but I don't have a 20K VR. Would 10K work or its a bit too low?

[Kabauterman]

I did the OCP mod and it works bekause i can run the end of the Aquamark with 1,4V Load but all volts over 1,20 doesnot work and crysis will freez no matter which clock is set.

same problem qith my OCP mod :-(

I solder 2 25kohm VRs (setup to 4 kOhm) across the 2 SMDs
but all over 1,2 V Freezes in the test :-( no matter what Clocks I setup

The Soldering points have contact and I do all what the Pictures say

[aoch88]

Can someone help to tell me where I should twist my multimeter to read the voltage for the 8800GT? My knowledge in electrics is somewhat limited and I don't know which is AC/DC by the symbols



Also, can I use 10K ohm for Vmem? I hope 10K wouldn't generate too much voltage increase.

[natedog420]

20 on the V-. left side on the dmm

[Ceph]

same problem qith my OCP mod :-(

I solder 2 25kohm VRs (setup to 4 kOhm) across the 2 SMDs
but all over 1,2 V Freezes in the test :-( no matter what Clocks I setup

The Soldering points have contact and I do all what the Pictures say

How can I measure if i did the mod right? I solder a 3,92 KOhm on the 2 SMD.

[jason4207]

You can use math and a DMM.

The original resistance is 1.29k, and your putting a 3.92k in parallel, so using this link we can calculate that the resistance should be ~971 after the mod.

[Ceph]

yes one have a resistence of 9,1 and the other 4,00

[Ceph]

You can use math and a DMM.

The original resistance is 1.29k, and your putting a 3.92k in parallel, so using this link we can calculate that the resistance should be ~971 after the mod.

Thanks a lot! I tried the OCP mod once again and it works. One resistor seemed to be over heated (My soldering skills arenot very high). Now with the new one the card does very well. I will try some new clocks!

[quake6]

What resistance to use,can I use 1.2k ohm? Or it is better to use 2.2k ohm or? For OCP...What is better for higher clocks and voltage?

[aoch88]

I need some help here. I bought a Galaxy 8800GT with dual slot cooler and the PCB layout is totally different from nVidia reference board. To make it even worse, it isn't the same as the Galaxy board which we can find in this thread.

I wonder if anyone else have the same card and how do I volt-mod it? It has the jumper and I've set it to what is supposed to be 1.3V but using the multi meter to get the vGPU reading also doesn't work.

It comes with Samsung RAMs so I've no idea if that is better compared to Qimonda? Someone give me a clue please

[jason4207]

Well i didn´t check the volts with any voltimeter, but here is a screen shot of what i did with the bios and like i said eariler this card is not mine. I could have tested more with it if i had the chance.

Meanwhile i can increase the core to 850mhz but it´s pointless, like i said eariler i don´t own a 8800GT

Let's see a ss of 850 running please.

[largon]

I need some help here. I bought a Galaxy 8800GT with dual slot cooler and the PCB layout is totally different from nVidia reference board. (...)

I've been working on that card for some time now.

[Renegade5399]

On that galaxy, you should be able to do a minor volt mod with just the jumper by the power connectors.