For all 6800gt owners, besides Gainward Golden Sample, and Asus owners, your 6800GT video card's core voltage in 2d mode is 1.2V and 3d is 1.3V. As some of you probably know, to get good overclocking results on a CPU requires to raise the Vcore, well on the video card it's the same thing. Raising the voltage on your 6800gt from 1.3V to 1.4V gives significant results, however not all cards can handle this, after reading some forums, many brands of cards cannot handle the slight increase in voltage, the 2 brands that are almost guranteed to fail are BFG and PNY, but you could still give it a try.
This process is fairly simple, and in my opinion foolproof, but just in case you do screw up, you can always flash it back using a PCI card to boot computer.
Okay first of all you'll need the following things,
1. Floppy drive
2. Floppy disk
3. Download the program NiBiTor
4. Download the NVflash utility
First to back up your original bios:
-Create a bootable floppy disk, then copy the NVflash files onto the floppy.
-Set computer to boot from floppy in bios
-after the floppy disk has loaded, type "a:nvflash -b backup.rom" without quotes, then press enger. this will save your current bios on the floppy as backup.rom
There you've backed up your current bios, in case the new bios doesn't work out just flash back to this.
Now reset computer and go back into Windows, open the backup.rom file on your floppy disk using NiBiTor, now press the voltage tab, and set the 3d voltage from 1.3V to 1.4V, now save the file on the nvflash floppy you just made as newbios.rom
Here's how to flash your card with the new bios:
-Boot from the floppy with NVflash and the newbios.rom
-After floppy's loaded type "a:nvflash -p -u -f newbios.rom" without quotes, and press enter.
-Reset computer, and go into windows, it shouldn't have problem with driver, since you only modfied your own bios.
You're done, you just increased the core voltage to 1.4V on your card, happy overclocking.
Now if the card behaves strange in any way in coolbit, such as crashing when you press the test button, that means your card sucks and can't handle 1.4V, flash back.
Here's how to flash back to original bios.
-Boot from nvflash with backup.rom floppy
-type "a:nvflash -p -u -f backup.rom" without quotes and press enter.
I think i covered everything, if i remember anything else i'll update this. This is a very simple process, and can't go wrong, so if you got all the stuff i said you'd need, then give it a try. If your card sucks and doesn't work out, hey just flash it back, you got nothing to lose.
Okay, have to mention this in the end, if you're a dumb@ss and screw up your card, I am in no way responsible, you do this at your own risk.
JK, as for the answer to your question, to my knowledge, I haven't seen any successful bios mods, but I haven't seen enough, i've only seen about 20 cases, and they've all failed. You'll just have to try it and have a PCI card nearby handy, so you can flash bios back if it screws up.
I have bios modded 2 6800 OC cards so far. 50% success rate. Both unlocked the extra pipes just fine. But one is an older model with different caps.
The older model has all large caps on the power supply circuits. The one that did not work has 5 large caps and 3 small ones.