[Pyr0]

Geforce 7800GT BIOS mod

Since the 7800 cards were released, people have been doing voltage mods using variable resistors to gain higher overclocks

Recently it has been found to be possible to gain 0.1v just by modding the bios of the 7800GT cards
Unfortunately, it is doubtful that this mod will work for the GTX cards though, as they may already use the higher voltage available.
Of course you can try the mod, and if it doesn't work, then you can always flash back your original BIOS. Just make sure you always backup before flashing

To do the BIOS mod, you will need the following:

a couple of floppy disks
NiBitor 2.5a
NvFlash 5.31
**See below for updates**
Nibitor 2.8

First you will need to make a backup of your bios just incase:
Create a bootable floppy disk and then copy nvflash.exe and cwsdpmi.exe to the same disk
Boot the computer from the floppy, and issue the command:
nvflash -b a:\oldbios.rom
This will extract a copy of your video card bios and put it onto the floppy disk as oldbios.rom

Before you continue, you should be aware of the risks involved
I cannot be held responsible for any mishaps you may have or damage you may cause to your card. Incorrect flashing of your card can render it inoperable, and leave you staring at a blank screen.
To minimise the risks, you should have an old spare pci graphics card and/or a floppy disk containing your original bios.
If anything should go wrong and you don't have a spare pci gfx card, then you can still do something known as a "blind flash"
To do a "blind flash" we add the following lines to the autoexec.bat file on the floppy disc containing your original backed up BIOS:
nvflash -r
nvflash -4 -5 -6 -A -y a:\oldbios.rom
This will flash the bios of the videocard without requiring any user input

Right, with the warnings out of the way...

Boot back into windows and open your bios file with NiBitor. You should see something similar to the following screen

Now comes the strange part, change the device id to read "Nvidia PCI-E 6800 Series GPU" and save the BIOS under a different name (eg. newbios.rom)

Open the new "newbios.rom" file and switch to the "Voltages" tab, place a tick in the "Extended Voltage Table" box


This allows us to select 1.5v as a 3D value


next we must clean up and correct the voltage table entries


the correct listing should be


after correcting the table entries, change the device back to read "Nvidia PCI-E 7800GT" and save your modded 7800GT BIOS

make yourself another bootable floppy disk and add the nvflash.exe, cwsdpmi.exe, and your newbios.rom file
reboot the pc with the floppy, and type
nvflash -r
nvflash -4 -5 -6 -A -y a:\newbios.rom

This method worked perfectly for my BFG 7800GT OC card, the nvidia driver now detects the optimal frequency of my card as 499/1.20

It also gained approx 300 points in 3dmark05 going from approx 7900 to 8200
Previously before the mod, I would get screen corruption when running the core above 475MHz

I may try the hard mods for memory and core voltage at a later date

Update: NiBitor 2.8 has been released, it adds support for x64, and makes the process slightly easier.
Among other changes including support for the latest 7900 cards, you can now read the BIOS from your card within Windows x64 just as with x86
There is no longer any need to change the device id to read "Nvidia PCI-E 6800 Series GPU".
Instead, just place a tick in the "Extended Toltage Table" checkbox

[Athildja]

Thank for this Pyro,

To this I will also add:

PlanetAMD64.com is not responsible for any damage that may occur to your card from the use of this information.

Use of this information is AT YOUR OWN RISK


now Pyro will that work on a GTX?
or is this limited to the GTs?

[Pyr0]

well i've just been playing with a leadtek 7800gtx bios and it looks possible, unfortunately i don't have a GTX to test it on :s
although this time, i didn't change to the device id to a 6800 card first, i just edited the voltage table, added the 1.5v entry, and changed the 3d to 1.5

why don't you try it Ath

This post has been edited by Pyr0: Dec 6 2005, 01:26 PM

[Athildja]

when I have time.
right now I am extremely busy. I may give it a shot later. I will also want better cooling first.
thanks again for the info Pyr0.

[Pyr0]

you're welcome mate
i just hope it can benefit some more peeps as much as it did me :)

oh, and i've just changed the default cooler on my BFG for a Zalman vf700cu - much quieter

This post has been edited by Pyr0: Dec 6 2005, 01:29 PM

[Athildja]

one of My GTXs will run 499/ 1435 stock but after a while it does get sort of "warm"
I think I could get close to 525 with a slight increase in voltage and better cooling.

[Pyr0]

do those cards have standard speeds of 450/1250 ?

[Athildja]

yes.

[TomCat_Ri]

Pyro, do you need to run VF700 at 12V on that 7800GT after voltmoding? And have you had to run it at 12V before? So, is 5V enough to cool this card?

[Pyr0]

Hi TC
i only put the Zalman on yesterday, after doing the bios mod. i just guessed that it would cool better than the stock heatsink
i haven't tried running the zalman at 5v since putting it on this card, although it is connected to a fan controller
at 12v, the maximum temp so far (as recorded by motherboard monitor 5) has been 58C
but even running the fan at 12v, it's still a lot quieter than the stock heatsink

This post has been edited by Pyr0: Dec 6 2005, 02:09 PM

[Bile_Hazard]

A nice How-To, Pyr0

[Pyr0]

hehe, thanks Bile Hazard
pictures speak a thousand words

[TomCat_Ri]

Hi TC
i only put the Zalman on yesterday, after doing the bios mod. i just guessed that it would cool better than the stock heatsink
i haven't tried running the zalman at 5v since putting it on this card, although it is connected to a fan controller
at 12v, the maximum temp so far (as recorded by motherboard monitor 5) has been 58C
but even running the fan at 12v, it's still a lot quieter than the stock heatsink

Do you have a converter to 5V? You should have one... it comes in the box with VF700. If you have time, please, connect it and let me know, thanx.

[Pyr0]

i set my zalman to 5v, and ran 3dmark05 for a couple of loops
motherboard monitor says that the maximum temp reached was 66C with an average of 56C
not too bad for running silently
i can't really hear it when it's on 12v, so i think i'll leave it on the high setting to keep the temps down

[edit] lol, i should add that some of my memory is naked hehehehehehe
this zalman was on my old geforce 6600gt, and the memory heatsinks have lost some of their stickiness
i just found one stuck on my watercooling radiator at the bottom of my case LOL
i guess it's time to buy some more
...although there doesn't seem to be any adverse effects to them not having ramsinks on

[edit] on 12v the max temp reached after approx 1hr of gaming is 60C

This post has been edited by Pyr0: Dec 8 2005, 08:20 AM

[darealraz]

is there a solution like this for ati cards?

[Pyr0]

erm....
depends on the card, some of them can be flashed to the next model, unlocking pipelines and so forth.
but as far as i know there aren't any volt mods available using the bios

a hardmod may be possible are you any good at soldering?

[darealraz]

i have a x700 pro. no im not good at soldering anymore. u said some models can be flash to unlock pipelines? do you kno which models?

[Pyr0]

i'm sorry, i've had a little look for anything on the x700 and unfortunately all i could find so far is a hardmod for the core and memoy voltages:
http://www.techpowerup.com/articles/overcl...ng/voltmods/117

[darealraz]

damn o well. thx for the help

[sparkyz]

I seem to be having trouble getting this utility to run properly.
The UI loads fine but can't detect the bios.

Error from event viewer:
??\E:\ARCHIVE\v2.5a\nibitor.sys has been blocked from loading due to incompatibility with this system. Please contact your software vendor for a compatible version of the driver.

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