Gigabyte 8600GT Vmods

[Paulo Jorge]

Bought this card about a week ago, firsts oc's only 650Mhz gpu stable.

Got some artifacts with only 10Mhz more.

Tried to look for some vmods for this card and nothing, only found a guide for bios mod on gf cards.
Tried out and put 1.5v on core ( default is 1.32). Tested and yet the same artifacts at the same speed.
Incresead to 1.8v (saw the max volts in shaminos guide) and yet nothing...

What did i do?

Start searching for the PWM controller in the card.



and get the datasheet to NexSem :



Measure resistance between FB and GND :



wich is 50K. Got some pot's in home but i can't find vgpu and vmem measure points. So i calculated it

Vgpu(new) = Vgpu(old)*(Rgpu/Rgpu(new))

Set the pot to 40K and that gives 1.6vgpu since this core has 1.32v default (saw it in NiBiTor)



Don't wanna end the warranty for now, so i grab a grabber...



A little bit more mem refrigeration ( got wc on gpu )



Results :



Pushed a little for the mems



And the final benching results :



Tell you guys one thing, . Only with 1.6Vgpu hit 800Mhz in core, 783Mhz benching in most of 3D01 tests...

Missing VMem but tomorrow going to google for the chips and see the max V they can handle...

We got card i think....

And this 148 still amazes me , only 1.6vcore and benching at 3.1Ghz... Still got buy a C2D....

Some updates on mems for the next week maybe (got a lot exams this week... )

[nullface]

Oh MY GoD!!! 800 Core - that is damn high, expektet around 700-730 from this card.

But yet again, i dont get it, the mobo's PCI-E 1.1 slot only is able to give 75W right? And the 8600GT does NOT have a power connector, so does it realy dont need more than 75W max to run at these speeds?

Or have i missunderstod something?

[Paulo Jorge]

Oh MY GoD!!! 800 Core - that is damn high, expektet around 700-730 from this card.

But yet again, i dont get it, the mobo's PCI-E 1.1 slot only is able to give 75W right? And the 8600GT does NOT have a power connector, so does it realy dont need more than 75W max to run at these speeds?

Or have i missunderstod something?

You're probably right. Only have the power from the pci-ex. Already planned to give it a overboost but haven't the time yet...

Cheers

[Mad_Man]

You're probably right. Only have the power from the pci-ex. Already planned to give it a overboost but haven't the time yet...

Cheers

i have 8600GT too, but from MSI... mem is overclocked from factory to 800mhz, and core to 580core/1188shaders, but im able to run it at 648/1350 45C load, anything higher it artifacts like mad..
as i see your results, im gonna try that myself, but i must found smth to chill my Vmem.

May i beg you, if you find the way how to feed it with more than 75W, please, let me know about it.

[Nosfer@tu]

I dont recall where I got the picture form. Belive it is here on XS, I just took it that it works.

BUT I HAVENT testet it and hvae no no way of sating if it works
Just wanted to try it one day

[leoftw]

That picture is the main reason I was in this thread. LOL I think he got it to work .

[Mad_Man]

yes i saw that pic before, but mine card is 8600GT reference layout, and there aint "unused PCI-E power plug" as it seems he soldered the wires where power plug has to be, but wasnt from factory.
dunno

[KiD0M4N]

Oh MY GoD!!! 800 Core - that is damn high, expektet around 700-730 from this card.

But yet again, i dont get it, the mobo's PCI-E 1.1 slot only is able to give 75W right? And the 8600GT does NOT have a power connector, so does it realy dont need more than 75W max to run at these speeds?

Or have i missunderstod something?

Ok hold on: The PCI-e 1.1 slot is speced upto 75W. I don't think they have a "Wattage" limiter built in anywhere in the motherboard. if your main motherboard rail (the big fat 24 pin connector) is able to handle extra power load... heck it will easily handle more power draw (provided the motherboard isn't going to overheat from all the extra current being drawn over the traces...but IMHO it should be fine... the C2Ds draw current like mad :P)