8800GTS 512Mb (G92) vMods

[aussie-revhead]

Guys , have the Samsung chipped cards emerged yet ? Can you tell which has samsung ?

[pchs]

I have find this vmod....

[most_wanted]

I have find this vmod....

Test it man. lol

[jason4207]

Well,having a great Twintech card here on air.Looking after v-mod for 900/2200/2200 for 24/7 considering that without a v-mod i am stable at 820/2000/2200 and 840 for benching. And yes it does have Samsung memory

http://forum.crazypc.ro/attachment.p...6&d=1201826049

Awesome! You've got a good start. Let's just hope it scales well. If you decide to play w/ the memory voltage, please let me know if those Samsung chips responds better to higher or lower voltage.

Wonder if we could decouple VDDQ from VMEM..

I asked Viper about this, and he seemed to think it wasn't possible. I really hope he's wrong, though!

Q6600 @ 515 x 7
Crucial Ballistix Tracers 617mhz 5 5 5 5 T2
XFX 8800 GTS 512 – core 880 – mem – 1050 – shader – 2100
ASUS P5K Deluxe

3DMark01se – 70793

3DMark05 – 23519

Q6600 @ 450 x 8
2 x 1GB Crucial B Tracers 562.5mhz 4 4 4 6 T2
XFX 8800GTS 512 – Core 880 – Mem 1050 – 2100 Shader
ASUS P5K Deluxe

3DMark06 - 17382

3DMark03 – 50225

How did you get your FSB so high (515) w/ the quad? Just a good chip?

I have find this vmod....

Let me know if it works. From what I understand a BIOS mod won't work. The GT had a mod b/c there were 4 VID values assigned (0-3), and only the 3rd VID (2) was selected in the stock BIOS. By selecting the 4th (and highest) VID (3) you were able to get 0.05v extra...no more. With the GTS the highest VID is already selected, so there is no way to select a higher one.

I just looked at the BIOS file, and I'm sure it won't work. All they did was change the label for the VID (I tried this on the GT as well before I understood more about how it works). VID3 is still seen as 1.15v by the chip even if you change the label to 1.35v. VID3=1.15v; you can call it whatever you want, but that fact doesn't change.

[STEvil]

I asked Viper about this, and he seemed to think it wasn't possible. I really hope he's wrong, though!

It will require cutting traces and/or lifting legs on IC's I believe. I havent taken the time to look into it much yet though

[VoodooProphetII]

Hey Jason, I think I was just lucky with the chip, meaning good chip. But its 515fsb with only two cores. Can go up to 525 but air cooling holding me back.

[largon]

STEvil,
One would have to desolder all RAM chips and cut the connections between vDD and vDDQ solder pads. Then build vDDQ it's own power regulation circuit.

->
Impossible.

[Pacha]

Guys , have the Samsung chipped cards emerged yet ? Can you tell which has samsung ?

I've just bought a GT (Twintech) this week and it has samsung chips so I guess that some of the recent GTS may have samsung chips

[LuckyX2]

Somethign sounds wrong to me if you used a 50k VR for vMEM and get 2.35V minimum. WIthout the mod what is your resistance from the leg to ground?

Thanks for the help, I have a Modded 8800 and a stock 8800 the both read .6ohms resistance from the leg to ground.

And I dont think the problem was my 8800, after trying a differnt gpu/ram/psu I concluded it mas my board.

Here's some pics of my 8800 GTS 512

[maxwolfie]

So in summary -

Buy a 500ohm VR instead of a 1K ohm?
Is the 50K OK? Or lower?


I don't get why we need a 50K VR when we are only potentially setting it to around ~600ohms anyways, why not just get a 1K VR here. Same with the 1VR, why not just get a 250ohm? Makes no sense, unless I'm wrong (which I probably am)

[largon]

maxwolfie,
500Ω and 20kΩ VRs are fine for vGPU and vMEM mods respectively.

Infact, we are not setting the 50kΩ VR in the vMEM mod to anywhere near 600Ω at all. We're using the 50kΩ VR to set the whole circuit to ~600Ω. The catch with the high rated VRs is that the added VR and the preinstalled SMD resistors are installed in parallel thus resulting in a bit different combined resistance than either components separately.

[maxwolfie]

Are ovp or ocp mods necessary? If so, what components are required? Heading to elec store now

maxwolfie,
500© and 20k© VRs are fine for vGPU and vMEM mods respectively.

Infact, we are not setting the 50k© VR in the vMEM mod to anywhere near 600© at all. We're using the 50k© VR to set the whole circuit to ~600©. The catch with the high rated VRs is that the added VR and the preinstalled SMD resistors are installed in parallel thus resulting in a bit different combined resistance than either components separately.

[maxwolfie]

It's the same principle as for G80GTS:

This pic is of a GT so there's no SMD for 3rd phase...

1. I have also purchased these resistors - Please confirm that the photo there is actually a G92 and not a G80? Or at least confirm that it won't bugger my G92 if I try it? I'm only running the stock fan anyways so I might not even NEED to do these mods. I've read that it's only necessary for big vgpu increases

2. Is that the OCP or OVP mod?

3. Also, can I use normal resistors instead of SMD resistors, as my elec store did not have SMD (only capacitors)

4. One more thing, in regards to the actual vgpu/vmem mods - There are a couple of different types of VR's available - 20KOHM MULTITURN CERMET TRIMPOT, 20KOHM SPECTROL 25 TURN TRIMPOT and the open carbon type which I have purchased but are almost IMPOSSIBLE to adjust without going waaaay past the desired value! Hence me searching for 500 ohm and 20k ohm VR's instead

[T_M]

why not just get a 1K VR here. Same with the 1VR, why not just get a 250ohm? Makes no sense, unless I'm wrong (which I probably am)

Yes you are wrong.

[maxwolfie]

Ok, I will stick with the 500ohm and the 50Kohm instead, as per your original instructions

Cheers

[maxwolfie]

1. I have also purchased these resistors - Please confirm that the photo there is actually a G92 and not a G80? Or at least confirm that it won't bugger my G92 if I try it? I'm only running the stock fan anyways so I might not even NEED to do these mods. I've read that it's only necessary for big vgpu increases

2. Is that the OCP or OVP mod?

3. Also, can I use normal resistors instead of SMD resistors, as my elec store did not have SMD (only capacitors)

4. One more thing, in regards to the actual vgpu/vmem mods - There are a couple of different types of VR's available - 20KOHM MULTITURN CERMET TRIMPOT, 20KOHM SPECTROL 25 TURN TRIMPOT and the open carbon type which I have purchased but are almost IMPOSSIBLE to adjust without going waaaay past the desired value! Hence me searching for 500 ohm and 20k ohm VR's instead

By the looks of other peoples' mods, I'm after the 25 turn trimpot. I'll go grab 1 x 500, 1 x 1k and 1 x 50k now. Also 2 x single pole single throw switches so I can turn the mods off iif needed

[T_M]

Switches for the mods are good, but only switch on the mods with the system off or else you will likely trip some safety in the video card that protects against rapid voltage increases, and the system will reset.

[maxwolfie]

Yes you are wrong.

Help me to understand this then?

Because even with a 500ohm VR, I'm finding it near impossible to get 13.x ohms. It jumps from 8 - 20 ohms even with the smallest adjustment

Why such a large VR? I must not understand properly

[maxwolfie]

Righto, mod failed. I don't have the stable hand or a decent enough soldering iron to be doing such intricate work

*sigh*


Are any of the points able to be accessed on the other side of the PCB? Especially the tiny solder point for the vgpu. I've taken all the solder off it now, so I have no chance.

[largon]

1. I have also purchased these resistors - Please confirm that the photo there is actually a G92 and not a G80? Or at least confirm that it won't bugger my G92 if I try it? I'm only running the stock fan anyways so I might not even NEED to do these mods. I've read that it's only necessary for big vgpu increases

The pic is of a G92GT but it applies also to G92GTS but wit a third SMR.

2. Is that the OCP or OVP mod?

That's OCP. There is not OVP mod for any G92 based boards (afaik).

BUT!
OCP shouldn't be a problem for G92GTS as it has (atleast) 3 phases. G92GT on the other hand could gain from OCP mod as vGPU is just 2 phase thus the phases peak above the trip-point easier.

3. Also, can I use normal resistors instead of SMD resistors, as my elec store did not have SMD (only capacitors)

Yes.

4. One more thing, in regards to the actual vgpu/vmem mods - There are a couple of different types of VR's available - 20KOHM MULTITURN CERMET TRIMPOT, 20KOHM SPECTROL 25 TURN TRIMPOT and the open carbon type which I have purchased but are almost IMPOSSIBLE to adjust without going waaaay past the desired value! Hence me searching for 500 ohm and 20k ohm VR's instead

I can atleast confirm that both Cermets and Spectrols are ideal for any vMods (I personally prefer Spectrols).

Help me to understand this then?

Because even with a 500ohm VR, I'm finding it near impossible to get 13.x ohms. It jumps from 8 - 20 ohms even with the smallest adjustment

Why such a large VR? I must not understand properly

Sounds like you're tuning the resistor BEFORE you solder it in.
WRONG! Don't do that.
Tuning the VR before soldering can possibly destroy the card (if you don't know what you're doing). Always set the VR the max value before soldering (unless directed otherwise). You are supposed to tune it AFTER it is soldered.

I explained why this is important earlier in post #286.

Are any of the points able to be accessed on the other side of the PCB?

There are no optional soldering points other than those depicted in G92GT vmod guide pic.

[maxwolfie]

Excellent, at least I understand now

Cheers

you guys must have pretty steady hands :P

[T_M]

For small detail soldering i always steady the iron with two hands and both elbows on table, and even then i still shake a bit

[s e t h]

i just use adhesive conductive paint like so: http://www.xtremesystems.org/forums/...ghlight=ghetto

worked fine on my 8800gts512 using 500ohm multi turn vr set to maximum resistence initially

[maxwolfie]

i just use adhesive conductive paint like so: http://www.xtremesystems.org/forums/...ghlight=ghetto

worked fine on my 8800gts512 using 500ohm multi turn vr set to maximum resistence initially

Very good! I'll try this tomorrow - Cheers!

[funkflix]

Hi,

recieved my 8800GTS today, but i just have some 200ohm VRs left! Will they work too for Vgpu? Thanks in advance.