The graphics card I'll be using is the GTX 460 1GB MSI Cyclone.
1. Download NiBiTor.v5.9 - Works with Windows 7 64-bit. You can also find newer versions here.
2. Download nvflash_windows_126.96.36.199 Works with Windows 7 64-bit. Latest version is here.
3. Move everything into one folder. For example: D:\GPU_Overclocking
4. Launch Command Prompt and get to the folder with NVFlash. For example:
To get to the D: drive
To get to the folder
5. It's very important to backup your original BIOS for multiple reasons. Name it to something you'll remember that it is the original BIOS.
Nvflash -b MSICyclone460Original.rom
6. Now, leave the Command Prompt open, you'll be getting to it in a bit. Launch NiBiTor.exe by double-clicking on it in your Windows Folder.
7. Click on File -> Open BIOS and select your original BIOS you just backed up.
8. You'll see your info update on NiBiTor. Now click on Tools -> Fermi Voltage.
9. The Fermi Voltage Editor will pop up. Click on the Limit dropdown box and select the max allowed voltage, which is 1.2125v.
10. Click Apply and Click on File -> Save BIOS.
11. Rename the new BIOS so you know it's not the original.
12. Now that you have the updated BIOS with the unlocked voltage, you just need to flash it.
If you don't have your GPU's in SLI, then all you need to do is run this in the Command Prompt (substitute MSICyclone460.rom for your unlocked voltage BIOS name):
Nvflash -4 -5 -6 MSICyclone460.rom
If you do have your GPU's in SLI, then run this to find out what position they're in:
Then when you find your GPU's, flash each one individually (assuming they're both the same identical cards):
Nvflash -i0 -4 -5 -6 MSICyclone460.rom Nvflash -i1 -4 -5 -6 MSICyclone460.rom
13. Reboot your computer just to be safe. If everything's okay, go to MSI Afterburner and you'll see that your new limit for Core Voltage is 1212mV.
NOTE: Please allow for adequate cooling before attempting high voltage overclocks. Not only do you need to cool your GPU, but your memory, and VRM's.