8800GT voltage mods

[oohms]

I found Vgpu, Vdimm, Vdroop mods (Gigabyte had already done the OCP mod for me )

There are also 4 more voltages that are controlled off a quad op amp which i have no idea what they are for. When i test these mods ill get some voltage readings, maybe it could be worth modding them as well

(Pics up hopefully tomorrow)

[aoch88]

As promised, here are some shots of my modded Galaxy 8800GT w/ Thermaltake HSF. I know the quality of work is not that good - I just like to mod and didn't manage to think of how to make it look nice as yet

[HitandRun]

What voltages and speeds do you get with this card right now?

[aoch88]

My vMem is at 2.15V and I'm doing 760/1910/1200
More vGPU and I'd like to hit 800/2000 for Core/Shaders hopefully

[scottc19]

I am just going to go cry for a couple years F!#(^$#@ quimoda chips suck!!! 1k stable and no more... 1023 for benching...
Nice mem clocks though

[aoch88]

I have to thank HitandRun and Largon for the mods really It's now the vGPU mod and hopefully to push the core/shaders a bit more.

[HitandRun]

OK guys this mod is only for the GALAXY 8800GT PCB model. I soldered the wire straight to the pin @ 22 (FB) on the L6713A phase controller! The resistance to ground was 2492 ohm so I choose a 50kOhm VR to do the mod. See the pictures below.





Here are additional spots to solder on if you don't feel comfortable doing it straight to the IC.



My OC is 810/1800 @ 1.35V idle. At this settings I can run AM3 and 3Dmark06 loops forever. The voltage will top out beyond the 1.4V mark a lot without any problems. Now, the problem is that something is still shutting me down when I try to add more voltage but I'm not sure if its OCP since my screen just freezes and the voltage is not dropping out to zero. Now I'll need some help from the PROS! Let me know what you guys think!

[aoch88]

Holy cow, we now have a vGPU mod Thanks HitandRun and I'd definitely try it out soon.

[os008]

Now, the problem is that something is still shutting me down when I try to add more voltage but I'm not sure if its OCP since my screen just freezes and the voltage is not dropping out to zero. Now I'll need some help from the PROS! Let me know what you guys think!

Same thing happening to me, it's driving me crazy, ...

First, any voltage over 1.2v makes the screen go black (monitor enters suspend mode) and the voltage drop to zero. I'll try to do the OCP Mod today and see what happens with this problem.

Second, even at stock speed games freeze randomly, BUT, if i press ALT+Tab it takes like 20 seconds and unlocks to return to the desktop, if i return to the game it freezes again and takes longer if i try to ALT+Tab again, it's so weird and driving me crazy, cause most of the time i don't know whether it's from the o/c or something else!

Thanks.

[aoch88]

Same thing happening to me, it's driving me crazy, ...

First, any voltage over 1.2v makes the screen go black (monitor enters suspend mode) and the voltage drop to zero. I'll try to do the OCP Mod today and see what happens with this problem.

Second, even at stock speed games freeze randomly, BUT, if i press ALT+Tab it takes like 20 seconds and unlocks to return to the desktop, if i return to the game it freezes again and takes longer if i try to ALT+Tab again, it's so weird and driving me crazy, cause most of the time i don't know whether it's from the o/c or something else!

Thanks.

Are you on a Galaxy card or it's a reference board?

[aoch88]

OK guys this mod is only for the GALAXY 8800GT PCB model. I soldered the wire straight to the pin @ 22 (FB) on the L6713A phase controller! The resistance to ground was 2492 ohm so I choose a 50kOhm VR to do the mod. See the pictures below.

Here are additional spots to solder on if you don't feel comfortable doing it straight to the IC.

My OC is 810/1800 @ 1.35V idle. At this settings I can run AM3 and 3Dmark06 loops forever. The voltage will top out beyond the 1.4V mark a lot without any problems. Now, the problem is that something is still shutting me down when I try to add more voltage but I'm not sure if its OCP since my screen just freezes and the voltage is not dropping out to zero. Now I'll need some help from the PROS! Let me know what you guys think!

Btw, where is the ground point which I can use near to the IC (pin22)?

[os008]

Are you on a Galaxy card or it's a reference board?

Reference

[HitandRun]

Holy cow, we now have a vGPU mod Thanks HitandRun and I'd definitely try it out soon.

Keep in mind this is all on your own risk! As you know from reading above I'm still fighting some kind of freezing which is not temp. related since this card never goes over 50C on full load.

Same thing happening to me, it's driving me crazy, ...

First, any voltage over 1.2v makes the screen go black (monitor enters suspend mode) and the voltage drop to zero. I'll try to do the OCP Mod today and see what happens with this problem.

Second, even at stock speed games freeze randomly, BUT, if i press ALT+Tab it takes like 20 seconds and unlocks to return to the desktop, if i return to the game it freezes again and takes longer if i try to ALT+Tab again, it's so weird and driving me crazy, cause most of the time i don't know whether it's from the o/c or something else!

Thanks.

Well, its not the same thing happening since my card never goes blank and drops the voltage! It just freezes. You need the OCP mod. Its cutting you off!

Btw, where is the ground point which I can use near to the IC (pin22)?

There you go! Some grounds for you!

[os008]

Well, its not the same thing happening since my card never goes blank and drops the voltage! It just freezes. You need the OCP mod. Its cutting you off!

I don't have SMRs right now, but tried to Pencil Mod it, and seems to have worked i think. Passed 1.4v on load but it didn't cut off, need more testing though, i just did a quick test.


As for the freezing ... i have that too ...

Second, even at stock speed games freeze randomly, BUT, if i press ALT+Tab it takes like 20 seconds and unlocks to return to the desktop, if i return to the game it freezes again and takes longer if i try to ALT+Tab again, it's so weird and driving me crazy, cause most of the time i don't know whether it's from the o/c or something else!

Did you try to ALT+Tab?

[jason4207]

I don't have SMRs right now, but tried to Pencil Mod it, and seems to have worked i think. Passed 1.4v on load but it didn't cut off, need more testing though, i just did a quick test.


As for the freezing ... i have that too ...



Did you try to ALT+Tab?

Pencil modding seems a little dangerous as you want the resistance across both SMC's to be equal.

[os008]

Oh, good point, i'll shutdown and measure the resistance ASAP. it should be 1.4K Ohm, right?

[aoch88]

Keep in mind this is all on your own risk! As you know from reading above I'm still fighting some kind of freezing which is not temp. related since this card never goes over 50C on full load.

There you go! Some grounds for you!

Thanks and yup, I do understand I'm on my own but at least you did it on yours and sure that it works If it doesn't work well, I'll just remove the mod by unsoldering. Btw, what resistance do I have to put to get around 1.35V? I'm just thinking if a 20K VR pot woudl work.

[noXqzs]

if he is using a 2492 ohm resistance, and a 50k 25 turn pot, then you should get higher precision with a 20k 25 turn. Even better would be a 5K.

[jason4207]

Oh, good point, i'll shutdown and measure the resistance ASAP. it should be 1.4K Ohm, right?

I believe it's 1.29k Ohms stock, and you'll want to end up somewhere around 985-650 Ohms. The lower you go on that scale the more OCP headroom you'll have, but you'll also tax the load-balancing the lower you go.

[HitandRun]

Thanks and yup, I do understand I'm on my own but at least you did it on yours and sure that it works If it doesn't work well, I'll just remove the mod by unsoldering. Btw, what resistance do I have to put to get around 1.35V? I'm just thinking if a 20K VR pot woudl work.

Don't know exactly but 50K got me booted up just below 1.3V so I think 20K will give you a little more than 1.35V. You got a good cooling so I would not worry about it! Just boot up and see what happens. I can't trip the OVP on this card even when I run this thing far beyond 1.4V but the OCP comes into play! More testing follows.

[Demo]

Why does that galaxy use 2 six PCIE power connectors?

[oohms]

A sneak preview:



I modded every voltage i could find, ill post an update after i test it.

[aoch88]

Don't know exactly but 50K got me booted up just below 1.3V so I think 20K will give you a little more than 1.35V. You got a good cooling so I would not worry about it! Just boot up and see what happens. I can't trip the OVP on this card even when I run this thing far beyond 1.4V but the OCP comes into play! More testing follows.

I tried looking at the IC and man, the legs are surely small I have a soldering gun which has a bad tip so I have no confidence in doing it until I get a proper one.

Anyway, there isn't anywhere else which we can solder?

[HitandRun]

Why does that galaxy use 2 six PCIE power connectors?

I think Galaxy claimed that the 3 phase power needed extra juice compared to the 2 phase PCB design. I might be wrong on this one!

A sneak preview:



I modded every voltage i could find, ill post an update after i test it.

This is INSANE! I love it! Which PCB design is this and which power regulator is on this card?

I tried looking at the IC and man, the legs are surely small I have a soldering gun which has a bad tip so I have no confidence in doing it until I get a proper one.

Anyway, there isn't anywhere else which we can solder?

YES! Look at the picture in my post above! I showed 3 different places where you can solder to on the backside of the card.

[aoch88]

YES! Look at the picture in my post above! I showed 3 different places where you can solder to on the backside of the card.

Ok, I think I got confused The 3 spots are the alternatives and I can just solder there with another wire to ground? Why did you chose soldering on the IC anyway? It's so difficult and tiny.