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M1710 7900 GTX Vcore mod

post #1 of 11
7/20/06 at 9:08am
Thread Starter 
Just got my 7900GTX today and oc to 620/715 runs great. The GPU temp max out @75C. I noice the default Vcore were 1.24v. I was wondering if anyone has try to raise the Vcore to get greater OCing result??
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post #2 of 11
8/8/06 at 10:32am
dito
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post #3 of 11
8/8/06 at 4:01pm
i don't think we have a good enough bios yet. nibitor
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post #4 of 11
8/8/06 at 10:22pm
Thread Starter 
I read an article online taht some guy did a 1.38v vcore at running his 7900gtx @700/750... wondering if someone willing to try first
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post #5 of 11
8/14/06 at 1:06pm
I tried do a vcore mod with nbitor and I tried the following settings:

650/750 1.3v -> freezes in 3DMark05 in the second test
650/750 1.34v -> not flashable ("devices is not supported")
650/750 1.39v -> not flashable ("devices is not supported")
675/750 1.34v -> freezes in 3DMark05 in first test after about 30 secs
675/750 1.39v -> freezes in 3DMark05 in first test after about 20 secs
700/750 1.34v -> freezes in 3DMark05 in first test after about 5 secs
700/750 1.39v -> freezes in 3DMark05 in first test after about 3 secs
725/750 1.34v -> 3DMark shuts down after starting the first test
725/750 1.39v -> 3DMark shuts down after starting the first test
725/775 1.34v -> freezes while booting windows
725/775 1.39v -> freezes while booting windows

That's all folks....I don't think we can get a better vcore by using nbitor, but it should be possible with another method I think...
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post #6 of 11
8/14/06 at 1:28pm
I'm pretty sure that manually changing the reference voltage (i.e. x.xx V) does nothing. It is the VID # that counts. If you change VID6 from 1.24v to 1.39v, you are only renaming VID6 and not changing its nominal value. The only way to bump up the voltage is to move up to a higher VID (i.e. VID7). Does the 7900gtx bios have the option for a VID7?
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post #7 of 11
8/14/06 at 3:24pm
The vid of the 7900 GTX is already VID7!!!!
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post #8 of 11
8/15/06 at 2:10am
Thread Starter 
So....vmod is a no go for 7900gtx??
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post #9 of 11
8/15/06 at 10:18am
Yeah I am trying it.
I got it to work with Nibitor fine? (version 2.9a)
Tools - read bios - select device - choose the card.
Tools - read bios - read into Nibitor.
Tools - voltage table editor
Change entry 2 to the voltage you want leave the VID alone.
Save it then use magic iso or whatever to add it to the boot disc image, burn to CD.
Use Nvflash to flash as normal.

My card has always artifacted with the core past 585mhz, it will run fine at 600/715 but ATITool shows bad artifacts, 585/715 is fine.

I started off with 1.3v then 1.33v, 1.35 and finally 1.4

Using detect optimal frequencies the only gains I could see was 5mhz on the memory and 2mhz on the core.

Using Nibitor to read the bios again after flashing shows the voltage as what I set it at but I am not convinced it is actually raising the voltage on the card, possibly a motherboard restriction?

I have tried Rivatuner but can't get it to read the actual voltage correctly, although it does tell me I am running at VID #7 which is set to the higher voltage.

Add me to MSN if you want to try one of the bios' I have modified.
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post #10 of 11
8/15/06 at 10:48am
Quote:
Originally Posted by Lukass
Yeah I am trying it.
I got it to work with Nibitor fine? (version 2.9a)
Tools - read bios - select device - choose the card.
Tools - read bios - read into Nibitor.
Tools - voltage table editor
Change entry 2 to the voltage you want leave the VID alone.
Save it then use magic iso or whatever to add it to the boot disc image, burn to CD.
Use Nvflash to flash as normal.

My card has always artifacted with the core past 585mhz, it will run fine at 600/715 but ATITool shows bad artifacts, 585/715 is fine.

I started off with 1.3v then 1.33v, 1.35 and finally 1.4

Using detect optimal frequencies the only gains I could see was 5mhz on the memory and 2mhz on the core.

Using Nibitor to read the bios again after flashing shows the voltage as what I set it at but I am not convinced it is actually raising the voltage on the card, possibly a motherboard restriction?

I have tried Rivatuner but can't get it to read the actual voltage correctly, although it does tell me I am running at VID #7 which is set to the higher voltage.

Add me to MSN if you want to try one of the bios' I have modified.

Thats exactly the way I did it but as you see in my results the vcore wasn't actually modded...Nbitor also showed me I was running the card at VID7 with 1,39v but with this high voltage it should be possible for me to run my card with 650/750 cause I'm already runnig it with 625/725 with no vcore modding, so I think it really could be a restriction, but maybe someone comes along with results that proof the opposite...
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post #11 of 11
8/16/06 at 2:35am
OK so I wasn't paying attention because it says quite clearly in the help file that...

Quote:
A entry consist of a label eg. '1.3V' as identifier for the driver
and
the actual VID eg. '03' which is set to the voltage regulator.
You must note that the voltage label is not responsible for the
output voltage, it is only used by the driver to select correct
VID.
So changing e.g. '1.3V' to '1.9V' will NOT give you
voltage of 1.9V, the voltage set by the entry's VID
will still be 1.3V.

I would be interested to try the other VIDs just to be sure but I am going to assume that we are sh!t out of luck.

The other problem is finding a way to accurately measure the voltage on the card.
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