7900GT Voltmod-2

Quote:

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Originally Posted by Nosfer@tu

Pulled some of the PCB and solder of form the 0.2 Vgpu stop :nono:

I solder the whires on, but it came of twice because I was reluctand to use glue, the PCB got pretty hot.

I Marked a littel Blue Cirkel where my whire pulled some of the PCB of.

I decidet to use the alternate soldering point marked with Yellow on the attached picture.

Everything worked Perfect, Card booted, And 0.05 and 0.1 Vcore was addet and resulted in 1.35 Vgpu :)

But 0.2 Volt did not work :(:(

QUESTION.
1. Did I kill the connection to 0.2 Vgpu when I "pulled" some of the PC and solder of the card??

2. How Can I acheave more then 1.5 Vgpu now when 0.2 Vgpu incresment
dosent work :(??

Thx for your help everybody :) Will poste some oictures of the card tonigth.

Ít works now :D
Just dident solder it the correct placew, was VERY tired after 16 hour values seminar at work

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soldering the right point does help :D When you solder these boards use a 15W soldering iron. It doesn't take much heat for these connections and using too much can damage your board, as you found out.

Quote:

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Originally Posted by t024484

When the voltage goes to zero, what is your 5Volt supply doing?
Diodes have a voltage drop that does not go to far beyond 0.7Volt, so if you measure 0 Volt, it can only mean that your 5Volt supply is going down.
The difference with the graphic board outside the computer is that there is no clock on the mem chips, and that no activities are taking place within the memory.
Once in the computer, the memory is adressed from the GPU and starts drawing real current.
If your 5Volt 15A power supply cannot deliver the current, it can only mean that one or more memory chips are ruined.
I am sorry, but it was worth trying.

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using 3.3v rail with 30A.

The voltage remains constant @ 1.9v with my power supply, the voltage actaully running through the video card drops to 0v when plugged into the motherboard (motherboard not even powerd up). Now, when I apply power to the motherboard this gives me a negative voltage reading. Again my power supply voltage is constant @ 1.9v.

Somthing must be cutting power to the card when it is inserted into the motherboard, as my power supply is supplying the correct voltage :confused:

Mabye I should just retire the old girl.

Cheers

C-BuZz

Quote:

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Originally Posted by C-BuZz

using 3.3v rail with 30A.

The voltage remains constant @ 1.9v with my power supply, the voltage actaully running through the video card drops to 0v when plugged into the motherboard (motherboard not even powerd up). Now, when I apply power to the motherboard this gives me a negative voltage reading. Again my power supply voltage is constant @ 1.9v.

Somthing must be cutting power to the card when it is inserted into the motherboard, as my power supply is supplying the correct voltage :confused:

Mabye I should just retire the old girl.

Cheers

C-BuZz

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Mate, grab another AU$500 and get another one. This time don't go over 1.55v core (with Zalman VF900) and don't mod the memory at all! Also heatsink those evil little mosfets.

I think that while you were very ambitious, you wouldn't try to drive your car at 100mph in 2nd gear would you? :nono: I did once (accidentally changed down) and blew all sorts of parts.

Quote:

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Originally Posted by smut

Its a 90mm fan bro, thats why you found it to NOT be a 80mm or 120mm :D.

But anyway I had an older 90mm TT fan laying around from back in the day when Newegg made a mistake and sent me a 90mm fan instead of a 80mm fan. They didnt want it back so I kept it, I remembered I had it last night and decided to switch it out since the side panel air flow is almost non existant. I never noticed until I was working inside the PC with the power on and I could hardly feel the air blowing from the side fan. I dust it every day just about because it get can dust on it rather easily. I just wipe it off with my hand and it gets the dust off of there. But yeah anyway find a 90mm fan and replace the stock fan if you'd like to get better airflow blowing on your card/mobo! Althought the stock fan is near silent and the more powerful tt fan I replaced it with is louder the trade off is worth it. Its blowing ALOT more air now which can only help!

edit: the link to the Thermaltake 90mm fan I replaced the old fan with. IM sure you can get it at newegg! Link to TT site here with fan model!

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Thanks for that. Did you notice the fan speed on the specs on that page?

285010% RPM LOL !

Quote:

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Originally Posted by xit

Mate, grab another AU$500 and get another one. This time don't go over 1.55v core (with Zalman VF900) and don't mod the memory at all! Also heatsink those evil little mosfets.

I think that while you were very ambitious, you wouldn't try to drive your car at 100mph in 2nd gear would you? :nono: I did once (accidentally changed down) and blew all sorts of parts.

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Thanks for your words of wisdom. But alas you are right. I definately wont be going that slow in second gear.. I'd want at least 150mph out of second. If it dies, it dies.. I can live with that.

@t024484, thx for your efforts, but I now fear the card has suffered long enough :) Time to put her back into the box she came in...

C-BuZz

Quote:

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Originally Posted by C-BuZz

Thanks for your words of wisdom. But alas you are right. I definately wont be going that slow in second gear.. I'd want at least 150mph out of second. If it dies, it dies.. I can live with that.

@t024484, thx for your efforts, but I now fear the card has suffered long enough :) Time to put her back into the box she came in...

C-BuZz

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I dare you to try to RA it....just clean it up a bit and say "it just blew up! And I'm mad coz it could have taken out my entire PC!"

:banana:

Quote:

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Originally Posted by xit

I dare you to try to RA it....just clean it up a bit and say "it just blew up! And I'm mad coz it could have taken out my entire PC!"

:banana:

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with 2 missing mosfets/wires hanging off it/diodes stuck it. Also 50K vgpu resistor soldered in place? No heatsink/dielectric greas all over it/insulation stuck to it front & back..

Hmm, wonder what the'd say?

C-BuZz

Guys, bios mod with Nibitor 2.8 worked for 7900gt xfx extreme edition 520/1500 ? i need change volt 1.2 for 1.4 , work??

[]´s Krause

Krause: if you have a question such as this (IE, off topic) start a new thread. bios mod is not the same thing as volt mod. Also, don't post your question in multiple threads, again start a new thread.

Quote:

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Originally Posted by C-BuZz

using 3.3v rail with 30A.

The voltage remains constant @ 1.9v with my power supply, the voltage actaully running through the video card drops to 0v when plugged into the motherboard (motherboard not even powerd up). Now, when I apply power to the motherboard this gives me a negative voltage reading. Again my power supply voltage is constant @ 1.9v.

Somthing must be cutting power to the card when it is inserted into the motherboard, as my power supply is supplying the correct voltage :confused:

Mabye I should just retire the old girl.

Cheers

C-BuZz

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I am puzzled by your mail. So you did not use a 5V supply with 5 diodes, but a 3.3Vsupply (probably a computer PSU) turned down to 1.9Volt.
Is this a separate power supply, or are you using the same supply that is feeding your computer?
How did you turn the power supply down to 1.9Volt?
How can on one end the power supply generate 1.9Volt, and have 0Volt on your graphic board with only two wires connecting the two?
Are you using very thin wires with a high resistance?

Anyhow, what I understand is that the board measures 1.9Volt outside the motherboard, and 0 Volt plugged on the motherboard, with no power on the motherboard. This means that there should be a connection between your 1.9Volt and something outside your graphic card, which is normally not the case.
I see three possibilities:
1) you have connected your 1.9Volt on the wrong position, it should be the large area under the unburnt Mosfet.
2) the Burnt mosfet area has a short circuit between the 3 source pins and the large drain area underneath connected to the 12Volt, or
3) somewhere else on your board is a short circuit because of the burnout between the 1.9Volt Vmem and either the 5Volt or 12Volt supply.

1) and 2) can be corrected, 3) is the end of this experiment

Quote:

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Originally Posted by xit

Thanks for that. Did you notice the fan speed on the specs on that page?

285010% RPM LOL !

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lol thats funny! I didnt notice that. Heres the real RPM of the packaging it came in, its 2850RPM at 35 dba.

Quote:

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Originally Posted by t024484

I am puzzled by your mail. So you did not use a 5V supply with 5 diodes, but a 3.3Vsupply (probably a computer PSU) turned down to 1.9Volt.
Is this a separate power supply, or are you using the same supply that is feeding your computer?
How did you turn the power supply down to 1.9Volt?
How can on one end the power supply generate 1.9Volt, and have 0Volt on your graphic board with only two wires connecting the two?
Are you using very thin wires with a high resistance?

Anyhow, what I understand is that the board measures 1.9Volt outside the motherboard, and 0 Volt plugged on the motherboard, with no power on the motherboard. This means that there should be a connection between your 1.9Volt and something outside your graphic card, which is normally not the case.
I see three possibilities:
1) you have connected your 1.9Volt on the wrong position, it should be the large area under the unburnt Mosfet.
2) the Burnt mosfet area has a short circuit between the 3 source pins and the large drain area underneath connected to the 12Volt, or
3) somewhere else on your board is a short circuit because of the burnout between the 1.9Volt Vmem and either the 5Volt or 12Volt supply.

1) and 2) can be corrected, 3) is the end of this experiment

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After a lengthy discussion with my local electronics store about my particular project, they recommended that I use the 3.3v/30A rail on a computer power supply. So I used 30A Bridge rectifier with 4 X .4v diodes inside it. Which drop the voltage .4v per diode. So total voltage drop across the 4 diodes is 1.2v. Leaving 2.1v remaining. They also recommended that I put a load on the circuit as the bridge rectifier does not actually begin working until there is a small load on the circuit. So I use 5W/1A resistor to put a small load on the circuit. After installing the resistor my power supply voltage was now 1.9v exactly.

I will take pictures of this experiment as it's quite difficult to explain.

Pics to follow.

C-BuZz

ok. i finally hit the limit on my stock coolers. i got to 1.5v mod but temps become an issue after that.
one of my cards is artifact free at 661/498(1992mhz) soo close to 2ghz.
and the other doesnt like me at the moment with the ram, but the core is better?!? 668/440 (1760)

i have lowere the load temp by 10*c by lapping the stock coolers and shaving a mil or so off of each leg. i also knoticed that the air from the fan is being blowen through the hole in the back of the stock cooler, so i taped it up, and its helped by another 5*c :D

i havent got any hot chips, which is strange, but i have to 2x80mm, 1x 120mm and 1x 120mm delta fans blowing at the gfx cards. :D and i still cannot here them over my chiller. lol

Pics.

Bridge rectifier used: (imageshack)
http://img60.imageshack.us/img60/527/34nd.jpg

Red wire +1.9V soldered to 4 x drain pins where mosfet used to be. If this is the wrong place, please draw where it should be connected. Black wire = ground.
http://img343.imageshack.us/img343/4403/18uq.jpg

With my power supply switched on I can test the vmem voltage & get good readings from many different points on the video card:
http://img343.imageshack.us/img343/9384/dscn04044ex.jpg

Here is my custom made power supply with 5W/1A resistor installed. This power supply is being used to power the card only. The motherboard has a separate power supply:
http://img53.imageshack.us/img53/5889/dscn04058fk.jpg

Now, when I plug the video card into the motherboard (motherboard not powered on) & I try to take a voltage reading from the card it reads 0v :confused:

But here's somthing to make you want to pull your hair out. My 1.9v (RED WIRE) in second pic above, if I take a reading at the solder point (where current is going into the card) it reads 1.9v!!!!!!!!!!!! Yet 0V @ vmem Measure point or any other point on the card.

I cant figure out what is going on, & why it is reading 0v when plugged into the motherboard & 1.9v when sitting on my table :confused:

C-BuZz

Quote:

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Originally Posted by coolingbug

Ive also seen/had a few cards loose this chip here. One leg burns up. Card still works, but perfomance is bad so check these chips really close guys.

http://img50.imageshack.us/img50/743/aa6oc.jpg

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what heatinks are you using there? I'm planning on getting the OCZ BGA (aluminum OR copper) ramsinks for the IC's by the vmem measure point, so the ones you pointed out that they get boiling hot.

OR you guys think TSOP heatinks will be better? and where can i buy them online US retailer?

Quote:

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Originally Posted by C-BuZz

Pics.

Bridge rectifier used: (imageshack)

Red wire +1.9V soldered to 4 x drain pins where mosfet used to be. If this is the wrong place, please draw where it should be connected. Black wire = ground.

With my power supply switched on I can test the vmem voltage & get good readings from many different points on the video card:
Here is my custom made power supply with 5W/1A resistor installed. This power supply is being used to power the card only. The motherboard has a separate power supply:
Now, when I plug the video card into the motherboard (motherboard not powered on) & I try to take a voltage reading from the card it reads 0v :confused:

But here's somthing to make you want to pull your hair out. My 1.9v (RED WIRE) in second pic above, if I take a reading at the solder point (where current is going into the card) it reads 1.9v!!!!!!!!!!!! Yet 0V @ vmem Measure point or any other point on the card.

I cant figure out what is going on, & why it is reading 0v when plugged into the motherboard & 1.9v when sitting on my table :confused:

C-BuZz

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You have placed a bridge rectifier behind the 3.3Volt. In that case you use only 2 diodes giving a voltagedrop of 0.7Volt each, resulting in 1.9Volt.
So far so good.

But, the red wire is connected to the large metal are under the BURNED mosfet (this is connected to the 12V) and not, as instructed, to the large metal area under the UNBURNED mosfet tho the left (Q501).

Your Black wire is connected to some funny point, but certainly not to ground. You should as instructed use the large round metal area around one of the 3mm holes, like the one to the upper left corner of the board.

Quote:

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Originally Posted by t024484

You have placed a bridge rectifier behind the 3.3Volt. In that case you use only 2 diodes giving a voltagedrop of 0.7Volt each, resulting in 1.9Volt.
So far so good.

But, the red wire is connected to the large metal are under the BURNED mosfet (this is connected to the 12V) and not, as instructed, to the large metal area under the UNBURNED mosfet tho the left (Q501).

Your Black wire is connected to some funny point, but certainly not to ground. You should as instructed use the large round metal area around one of the 3mm holes, like the one to the upper left corner of the board.

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Ok, so the red & black are in the wrong place :slapass:

Im not to sure what you mean by the large metal area under the BURNED mosfet. There is no large metal area under the mosfet. There is only 6 X Contact points under the mosfet. As you can see in the picture below. Please confim that I should attatch the 1.9v to the 6 x contact points circled in ORANGE.


Thanks


C-BuZz

Did the mod on the 2. Card now.

Accualy it came out quite good :)
But it was very hard to remove resistor J :(

Did it before on ic7 Max3 and the ic7 max2 aka Ic7-G.

But here it is quiet hard :(

Quote:

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Originally Posted by C-BuZz

Ok, so the red & black are in the wrong place :slapass:

Im not to sure what you mean by the large metal area under the BURNED mosfet. There is no large metal area under the mosfet. There is only 6 X Contact points under the mosfet. As you can see in the picture below. Please confim that I should attatch the 1.9v to the 6 x contact points circled in ORANGE.


Thanks


C-BuZz

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The 6 contact points that you mention are solder dots on a large metal area.
You connected to the metal area under Mosfet Q502 (the burned Mosfet), it should be the metal area, or as you prefer to call it ""6 contact points" under Q501. I have nothing at my disposal here to make drawings, but what I say should be crystal clear.

The memory voltage regulators on my card are crapping out and I am most likely going to have to go through with an RMA. If I get one of the new XFX 7900GT EE cards with the Black PCB, will I still be able to do the gpu volt mods? Thanks

Quote:

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Originally Posted by tranceaddict

The memory voltage regulators on my card are crapping out and I am most likely going to have to go through with an RMA. If I get one of the new XFX 7900GT EE cards with the Black PCB, will I still be able to do the gpu volt mods? Thanks

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Yes you will, but it will crap out on you as well...mine did..it's the second one I might add.

They definately will have to deal with this issue, doesn't matter if you mod or not...the mem voltage reg craps out sooner or later.:mad:

Quote:

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Originally Posted by Clint

Yes you will, but it will crap out on you as well...mine did..it's the second one I might add.

They definately will have to deal with this issue, doesn't matter if you mod or not...the mem voltage reg craps out sooner or later.:mad:

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I just ordered a 80mm Zalman thin fan to put on the back of the card and blow on all the regulators and MOSFETs. Hopefully this will prevent it from happening again.

i've done the 1.4 ink vmod
is there a 1.45-1.5vmod with ink ?

Quote:

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Originally Posted by Supertim0r

i've done the 1.4 ink vmod
is there a 1.45-1.5vmod with ink ?

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Did you read the thread dude? It shows how to doi t probably 5-6 times lol

Kind of an odd question for an overclocking forum, I know, but what if one was interested in undervolting a 7900GT? All the overvolting mods seem to be VID based, I was wondering if resistor mods were possible for this controller, or if there were any issues with this and that's why none are being posted.

Could I take the non-inverting input of the internal error amp (pin is called FB) high through a VR (set at max resistance, decrease resistance to increase voltage on the pin and reduce output voltage)? The only problem I'd forsee is according to the PDF for the controller undervoltage threshold is 82% of VID, which would give me space to ~0.95V. Doubt the GPU could even go this low, but if it can and this does end up being a problem I could just change to a lower VID code (say 1.1V) to offset the threshold down to ~0.85V, or basically as low as I need with the right VID.

Thoughts, suggestions, tips? Sorry I know this isn't terribly exciting for you overclocking guys, but I like tinkering with efficiency and low noise computing, so it's exciting for me. Any help would be appreciated. :)

I would prefer a resistor mod as it would easily allow me to undervolt until I encountered instability. With VID codes this would be very difficult, as I'm looking for the lowest undervolt possible but have no idea how low I could go. I guess it would be possible to rig up some kind of five switch system to pull each VID pin low or high, this would be a lot of work (almost to the point of not being worth it I think).