This is a simple guide on how to mod your Nvidia video card's bios and flashing it, and also how to backup/restore your original bios, just in case it doesn't work out.
 
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
5. Balls
 
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 enter. 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, modify it any way you like, change the voltages a bit, tweak the memory timings a little(BE SURE TO KNOW WHAT YOU ARE DOING!), increase/decrease clock speeds. Save the file 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. However if you've flashed to a different brand or different chipset's bios, you will need to reinstall your drivers.
 
You're done, your card now has the new modified bios
 
Now if your card behaves strangely, such as crashing in 3d, or artifacts, or crashes in coolbits, that means your card can't handle the new settings, and you'll need to restore to the original bios.
 
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.
 
Now if you screwed up majorly, your card wouldn't even boot anymore, you could blind flash the card back to the original bios, or you could use a PCI video card to boot the computer and monitor, then you can flash the bios on your primary card back to the original.
 
 
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.
 
 
Update: I will get an update soon on how to flash PCI Express cards and SLi setups.

I have a question...what the balls are for?...do you mean cojones?

On a note.
 
If you want to create an auto-recovery disk, create a bootable disk with nvflash and backup.rom on it, and then create a file called Autoexec.bat (Or edit the existing one), and put "a:nvflash -p -u -f backup.rom" in it (without the quotes).
 
That should do a blind flash restore.  Probably a good idea, just in case.

thanx for all,  I'll try when find an opportunity...

Maybe you can help me, I have an XFX6800GT, I set up a BIOS for 1.4v core. No problem flashing, but when I get into XP and try to overclock it won't, is there something I'm missing ?

should be 1.5 volts for the 6800

this doesn't work for pci express cards? It's only for agp I am guessing?  If that is the case it should really say, agp nvidia bios modification/flash/restore guide right?

 
HOW???

 
HOW???
 
If you have to ask that, you probably shouldnt be trying this, no offence!

Where do you actually get the new GPU firmware from?
 
I've always bought/used nVidia cards since ever since 3dFX went bust, and in all that time I've never seen an nVidia firmware available for download anywhere.

 
how do u blind flash?

Very, very carefully.

Thank you for reading my post and any comments on anything are apperciated.  
 
Ok I started my adventure down this dangerous road in an effort to have both fans on my 8800gtx's run 100% and a good OC.I know this can be done with RivaTuner but only on XP.I dual boot XP/Vista and did that but with Vista the drop down option for monitors only has one,so only one card is @ 100%.I didnt know there was a guide here for this and followed another thread's guidence,and this is what I did.  
 
Got Nibitor,saved original with Nibitor,made the changes I wanted and saved new bios.  
Got Nvflash and made the dos diskett with the Nibitor files.  
Before I flashed I did another back up in dos mode "nvflash -b stock.bin"...Noticed I used .bin and not .rom...The thread I read said to do it this way.  
It all went smooth untill I tried the new settings out in 3dmark06.It would freeze and I had to reboot,tried it again and same thing.Then it staring freezing without 3dMark had to keep rebooting,once it never maid it to desktop.  
Man I really messed up somewhere,I said "its all good I have a back up" so I start the procedure and restore the back up I made with Nibitor.Rebooted and said back to the drawing board....WRONG IT STARTED FREEZING AGAIN.  
So I then try to restore the other back up I made in Dos and it wouldnt let me.It said file must be .rom...ARGGGG  
I spent hours reading threads searching and found flashing in SLI wouldnt work each card must be done seperate.  
Took out each card and flashed it seperately with the OC bios I created and still no good FREEZING.  
I ended up restoring the original bios I made through Nibitor and crossed my fingers it would work...so far so good.  
Man what a waste of time and effort.Oh and buy the way I wasnt even able to change the fan settings,the option in fan boost was shaded out.  
 
Can someone tell me what I did wrong,and how if possible I can restore using that .bin file I created.I would of rather used that to restore.Thanks for reading this long thread and like I said any advice is welcome.  
 

 
 
Thanks dude, thats a good one    
 
Here is some guy telling you how to do exactly the same thing, but from within windows, at no risk of ballsing up
 
http://gnerma.wordpress.com/2007/1 [...] geforce-8/
 
I did this on mine and this is what I got:
 
Stock speeds:
Core: 500mhz
Shader: 1042mhz
Memory: 713mhz
 
After using RivaTuner and guide:
Core: 670mhz
Shader: 1762mhz
Memory: 1024mhz
 
Obviously you can flash to get the same results, but its less risky.
 
So, what does this mean for performance?
 
Core: An extra 35%
Shader: A massive 72%
Memory: An extra 44%
 
This means my GTS has literally doubled in performance, I run Crysis maxed out (no AA   ) at 1280*1024 at an absolute!! minimum of 30fps (usually during explosions and or intense physics activity), usually around 42/43, when it used to run around 30fps max!! I can post some screenshots if people don't believe me, since a GTX will just about do what I said. I don't mind, actually I'd quite like to.
 
Also there are hundreds of Crysis tweaks to squeeze a few more FPS and just to make it look better!
 
Disclaimer: Not every GTS will overclock exactly the same, I think I just got lucky!
 
Also, just incase anyone is going to try and say its not stable, I just ran around on Crysis for like 40 mins blowing stuff up, stressing it alot *around 32fps   * and it never missed a beat, or crashed.
 
Also, you may need to set your fan to 100%!! I do, its more noisy, but I don't actually care!
 
Anyone want to know anymore just ask  

UPDATE: a: nvflash -p -u -f <file name here>.rom no longer works on the new 8xxx series cards and with the newer versions of NVflash. The new command is a:nvflash --protectoff and then do a: nvflash <file name here>.rom

---------------
E2180 @3.2Ghz + P35DS3L +8400GS (700/475 OC)  

Yeah ^ that is correct ^.^
 
Stupid updates

Has anybody flashed their 8800GT? If you have done this what was the purpose? I have heard of flashing them for support for the AKimbo cooler by EVGA but does the bios update help anything else?

Hello
I have an 6600 silent edition from ASUS and i try to increase the voltage....
So I've done it and the next the computer doesn't power on(the screen) And now I have to reset the firware by hardware....Is there any way to do it???....