BFG 6600GT AGP Volt Mod Help ( Pics Inside )

[ISS]

I think I have found the resistors for the GPU mod. However, I don't think I will be releasing them. Those who are interested to try, pls PM me. Try at your own risk though. There are some things you need to take note.

Great job, this works a treat, here are my findings :


Giving it a little shade I reduced the resistance to 464.03 Ohms, this resulted in a voltage of aproximatly 2.41V. This had the following effect -

Stockvoltage at 2.1V - 3D Mark 2005 1 Loop No Artifacts

Auto Clock - 1.15Ghz
Manaul Highest Clock - 1.19Ghz

2.41V Voltage - 3D Mark 2005 1 Loop No Artifacts

Auto Clock - 1.16Ghz
Manaul Highest Clock - 1.21Ghz

Thanks for the help, can you please explain how you worked this out, such as which resistor on the photo relates to the diagram, as the entire reason I started this was to learn more ( My 6800 Ultra is better than my 6600GT :p ).

Roll on the GPU mod

[enzoR]

VGPU mod is right here

[dobbz]

VGPU mod is right here

Same for AGP?

IronFire, I might be missing something but I wouldn't think 10MHz is much of a gain, especially considering the 0.3v rise. My XFX does 1.22 artifcact free without any mod.

[IronFire]

Well either my card is rather sucky, the volt mod isnt working correctly or I need to try upping the speed via a BIOS flash, im open to suggestions.

[dobbz]

Well either my card is rather sucky, the volt mod isnt working correctly or I need to try upping the speed via a BIOS flash, im open to suggestions.

I have no suggestions in the electrical engineering dept. The only input I have is that when I'm playing with my OC, coolbits/rivatuner will sometimes let me set only 1.21GHz and sometimes it lets me do 1.22GHz, and I think it even depends on which drivers I'm using-- with 66.93 Forceware I first got 1.18GHz. After using 70.xx I'm at 1.22GHz. I think those margins are something to consider when you're looking at an apparent 10MHz gain.

[IronFire]

VGPU mod is right here

As far as I can tell this won't work on an AGP card.

[enzoR]

sorry i didnt realize that article was for PCI-X

[Eversor]

just tell us how to do the vgpu mod!!!
I'm dying to try that one out.

[zakelwe]

I thought I was doing the gpu mod last night as I put a vr on pin 4 for FB and was also surprised when the voltage did not go up .. I did manage to end up with opver 3v through the memory though

I should have read this thread first.

The spec sheets seem to show that the other IC is for DRAM but in this case it seems the 6549 is. The 6534 is it then but that has 3 FB pins.

Regards
Andy

[zakelwe]

Ok, it's pin 29 on the 6534, FB1.

http://www.aocb77.dsl.pipex.com/6600voltmod.jpg

This is roughly 500Ohms so I attached a 50k pot and set it at 10k. This gives me 1.20v measured on the caps, a few turns reducing the resistence and I am at 1.25v in BIOS ( and I assume 1.45+ in 3d ) so I will test it later.

There is a cap at the very bottom of the board and I think this more than likely shows the voltage for the AGP bridge chip, this seems set at 1.21v and does not go up with the gpu core voltage so that is good because that little bridge chip runs very hot.

Regards

Andy

[_Dejan_]

IronFire: Please can you send me this two PDF file?

[IronFire]

Sorry you have to e-mail Intersil directly for the files.


Ill try the core mod out when I have some free time.

[_Dejan_]

I send 1 weak ago mail to intersil (rlucas01@intersil.com) but nobody doesn't reply me.

[zakelwe]

I send 1 weak ago mail to intersil (rlucas01@intersil.com) but nobody doesn't reply me.

http://www.aocb77.dsl.pipex.com/ds-6549-13.pdf
http://www.aocb77.dsl.pipex.com/ISL6534_final_5.pdf

gpu mod only recommended if you have good cooling due to lack of low k on TSMC 0.11 micron process.

Regards

Andy

[zakelwe]

Here's the 6600 with both gpu and memory modded ( spot the two blue pots ) finally ended up at 635-645 core at 1.65v and 1231 memory at 2.15v.

http://www.aocb77.dsl.pipex.com/6600rig.jpg

Both vmem and vcore mods are very simple, the judgement comes with trading off temps with voltage on your cooling solution. Unless you have junked the stock heatsink I suggest you do not increases the voltage on the gpu much at all.

Regards

Andy

[_Dejan_]

zakelwe: Thanks for PDF.

P.S. How do you do this vmod? Do you have AGP version card?Do you put one variable resistor to FB1(29pin) and ground, and another var. resistor to FB2(32pin) and ground?

[IronFire]

Well I have done the GPU Vmod and it works but has no effect on my overclock

I used the little solder pad to the side of the IC's leg which is alot easier to solder to.




480 Ohms gave me 1.5090 V
475 Ohms gave me 1.5210 V
469 Ohms gave me 1.539 V

Yet my card will not overclock further than it did before at any settings, infact it actualy seems less stable with large texture sections in 3dMark 05 turning green at 590 Mhz with 1.539V yet with no volt mod they hardly ever apear.

What is affecting it ?

[zakelwe]

Well I have done the GPU Vmod and it works but has no effect on my overclock

I used the little solder pad to the side of the IC's leg which is alot easier to solder to.




480 Ohms gave me 1.5090 V
475 Ohms gave me 1.5210 V
469 Ohms gave me 1.539 V

Yet my card will not overclock further than it did before at any settings, infact it actualy seems less stable with large texture sections in 3dMark 05 turning green at 590 Mhz with 1.539V yet with no volt mod they hardly ever apear.

What is affecting it ?

Overheating ? What temps do you hit during a run using rivatuner if you leave riuvatuner diagnostic running as you do the run ?

Regards

Andy

[Eversor]

Well I have done the GPU Vmod and it works but has no effect on my overclock

I used the little solder pad to the side of the IC's leg which is alot easier to solder to.




480 Ohms gave me 1.5090 V
475 Ohms gave me 1.5210 V
469 Ohms gave me 1.539 V

Yet my card will not overclock further than it did before at any settings, infact it actualy seems less stable with large texture sections in 3dMark 05 turning green at 590 Mhz with 1.539V yet with no volt mod they hardly ever apear.

What is affecting it ?

I used a 10k resistor to ground, decreased to like 9k maybe, haven't measured yet, and it allows me to 633/1250, before only 590/1190. With no vmem mod.

I'm using watercooling.

[vkbms]

I've a Leadtek 6600Gt....I can't understand english very well....Could you make me a litle mod guide for Vgpu e Vddr???

§PS: Sorry 4 my English....

[Malachia]

vkbms ti traduco io np, appena capisco


guys plz pics of point where solder???

[TEDY]

tipical for italians...capiscono un cazzo

[Malachia]

tipical for italians...capiscono un cazzo

mo ti faccio la pelle

i'm only 17, my english is school level...but i think your italian is worse than my inglish, than shut up...

my problem here is not english, but electronic...

[vkbms]

vkbms ti traduco io np, appena capisco


guys plz pics of point where solder???

doesn't matter Malachia..... I've buyed a DFI NF4 with a _Leadtek 6600GT Extreme ....

[olgo2]

Hello,
I have this card agp 6600gt and a good cooling system (liquid, adapted hydrocool200ex).
I used a 20k variable resistor on the pin "u501" and the ground (my electronic knowledge is really poor, I suppose the ground is one of the black cable of the power sypply of the card, so I soldered there)
I decreased the variable resistance to 8,5k, I had no effects.
What the problem?
I hope to do an extreme overclock.....
Without any mod, with liquid cooling I have 600/1120 without artifacts.
Can someone explain the pencil method to a newbe as me?
best regards,
Antonio