8800GT/8800GTS G92 BIOS mod

[polobunny]

In this guide I will walk you through the process of modifying your 8800GT/8800GTS G92 BIOS to modify the default voltage and change your default clocks in 10 easy steps.

WARNING

Modifying your BIOS to raise the voltage and change your default clocks will likely void your warranty. Also, raising the voltage of your core will raise the heat output. Neither HardwareLogic or I can be held responsible for any problems that may occur. While those who already modified their voltage this way don't seem to have any problem, proceed at your own risk.


Tools you will need:

• USB thumb drive
• Computer capable of booting from USB, with Windows XP or Vista installed

Programs you will need:

• RivaTuner 2.08
• NVflash 5.57
• NiBiTor 3.8
• GPU-Z
• Dos-on-USB
• 3DMark06
• ATITool

Step 1:
If you are not safe modifying your voltage, you will need to find your maximum core, shader and memory frequency now. Zoom to Step 6.


Step 2:
Run GPU-Z and get hold of your original BIOS.
To do this, run GPU-Z and click the button circled in red.

Then click Save to file. Give it an easy to remember name ending in ".bin" and click OK.
Keep this file somewhere safe and don't modify it directly, always modify a copy of it.


Step 3:
Run NiBiTor. Go to File->Open BIOS and select the BIOS you saved using GPU-Z at the step before.
Select the Voltages tab and click OK at the warning prompt.
In the Exact mode tab, change the Extra value by clicking on the drop-down menu on the right and choosing 1,1v.
This is the maximum voltage the card can deliver to the 8800 G92 core.
The default for 8800 G92 core at idle is 1,0v.

Do not touch the clocks as of yet as it is totally unnecessary.
You can now save your new BIOS. Go to File->Save BIOS and save it under the NEW.ROM filename.


Step 4:
Now it's time to create a bootable USB drive. The easiest, fastest method I have found to do this was to use Dos-on-USB. Refer to the readme.txt file included with Dos-on-USB to learn how to create a bootable USB drive.
However, you do not need the files as instructed at Step 12 of the readme.txt file. You do not need to follow step 12 and over.
Copy your original BIOS file and your new modified BIOS file on the USB drive.
Extract the contents of nvflash to the USB drive as well. If you did everything properly, the contents of your USB drive should look like this:

If you do not see the files named command.com, io.sys and msdos.sys they might simply be hidden. Turn on viewing of hidden AND system files and they should be there. If not, repeat Step 4 properly.
In this picture, file.rom is my original BIOS and new.rom is my new BIOS.
How to see hidden files in Windows
System files box is under hidden files radio buttons.


Step 5:
It's always handy to have a backup PCI card in the case the flash goes wrong.
Reboot your computer and boot from the USB.
Once you are at the C:\ prompt, type this then press enter

nvflash -4 -5 -6 NEW.rom

Nvflash should ask you if you are sure about flashing the new bios. Press Y and wait until the process is done. Your screen might turn blank for a second while Nvflash updates the BIOS.
If for some reason or another Nvflash fails to update your card to it's new BIOS, type this then press enter

nvflash -4 -5 -6 file.rom

This will reflash the original BIOS to your card.

Once Nvflash is done, reboot your computer.
If everything goes well, Windows should now load.


Step 6:
Now it's time to find your maximum frequency. To do so you will need to install RivaTuner 2.08. Upon first starting RivaTuner, it might ask you if you want to check for updates. Accept. Then it will compile a list of your settings.
Personally, I like to set manually the fan to prevent overheating. I've heard reports that 80-85% is a good noise/cooling ratio for the 8800GT with 1 slot cooler. Your mileage may vary.
To do this, from the main RivaTuner 2.08 window, click the arrow circled in the picture below then the first icon.


This should bring you to a window looking like the one below. Tick the "Enable low-level fan control" box. You will be prompted for a reboot or a detection to properly detect your fan speed. Press the Detect now button. Tick the radio button labelled "Fixed" and set the fan level to your preference. Click Apply then OK once you are done.



Step 7:
At the main window of RivaTuner, click the arrow circled in the picture below then the first icon.

This should bring you to the Overclocking tab. Check the "Enable driver-level hardware overclocking" box and when prompted to detect the clocks, simply click Detect now. Untick the Link clocks box.

On 8800GT's volt modded to 1,1v I find 700/1730/1000 to be a good start to your overclocking. Since every card is different though, your mileage may vary. Take into consideration that memory frequency has very little overclocking potential as it is GDDR3 rated for 1Ghz. Do not lose time finding a value for this. Set to 1000mhz and concentrate on core and shader.
Click apply after selecting your base clocks.
I've seen 8800GT's go as high as 760/1800/1000 on 1,1v, to give you an idea.
While overclocking, it is important to go slowly, 10mhz or less at a time and test for stability between each step-up.


Step 8:
It's time to test for stability and heat.
To test for stability, I like to use 3DMark06. It puts a good strain on the video card. Install 3DMark06 Basic and go to settings part. Select "Repeat each test 3 times". Click OK and start 3DMark06.
You want to look out for any weird discolouration or protruding triangles/geometry. Anything that seems abnormal is likely abnormal. If your current overclock passes 3 loops, you can step-it up a bit. You will know when to stop overclocking when your computer or 3DMark06 crashes, freezes or you see strange behaviour.
To check for heat, I like to use ATITool "fur cube". Install and run ATItool then click the Scan for artifacts button. Still in ATITool, watch the GPU temperature closely. Wait 5 to 10 minutes. Ideally, the lower the better.


Step 9:
Now that you have found your maximum stable core, shader and memory frequency you can modify your BIOS to reflect those changes permanently.
Open NiBiTor and open your original voltage modified BIOS.
Verify that the voltage section is set accordingly.
Go back to the Clockrates tab and change the values in the Extra section.
Save your BIOS and flash your new BIOS as described in Step 5. Don't be foolish! Setting clocks too high as your default BIOS clocks can render your 8800 G92 series card unusable. Overclock intelligently and if you see that your RivaTuner frequencies aren't stable, they won't be anymore stable when set as default.


Step 10:
Enjoy your modified 8800 G92 series card! Gains should be substantial.





Next, physically modifying your 8800 G92 card, albeit non-permanently to raise the voltage even higher.

[Parker]

Oh sweet!!!!!!!! When I have some extra time I'm going to try this!

Great job PB! Can't wait for the "physical" mod!!!

[polobunny]

Man, the only thing keeping me from showing you is my crappy camera and my crappy picture taking skills. They all come out horribly blurry and since it's a very tiny spot it's a no go with blurry pictures. I'll really try to do something about it.

You'll need a few things, soldering iron, electrical tape, max 6 inches of 1 conductor 24 AWG stranded wire (easier with stranded than solid and nothing bigger than 22, I did it with 20 and it's a bitch), 1K ohm or 500ohm potentiometer (also known as variable resistor) and last but not least a multimeter. Hot glue is optional to stick the potentiometer somewhere on your card.

[theburan]

Really nice write up! I wish my card was happy running the memory at 1ghz... but it really isn't happy above ~950mhz from what I've tried. Thanks for sharing!

[Sumgai]

Originally Posted by polobunny

You'll need a few things, soldering iron, electrical tape, max 6 inches of 1 conductor 24 AWG stranded wire (easier with stranded than solid and nothing bigger than 22, I did it with 20 and it's a bitch), 1K ohm or 500ohm potentiometer (also known as variable resistor) and last but not least a multimeter. Hot glue is optional to stick the potentiometer somewhere on your card.

Sounds like this will be fun

[dttuner]

Great... I can't seem to get my system to boot off my USB. It detects it, and I even flashed my motherboard bios off of it... but can't get a dos prompt.
.

[Capper]

Head over to Bootdisk.com, they have apps that will make your USB/Floppy?CD/DVD bootable under a variety of situations.

[polobunny]

Originally Posted by dttuner

Great... I can't seem to get my system to boot off my USB. It detects it, and I even flashed my motherboard bios off of it... but can't get a dos prompt.
.

Did you try the Dos-on-USB thing I linked in the tutorial? :)