first u need rivatuner 15.2 which can be downloaded here
scroll down and click "I Agree"
the download should start
after its finished, install it
once it is installed, click Start, Programs, Rivatuner, Rivatuner
under Target Adapter click Customize, then click on the Graphic Card
Click NVStrap Driver
At the Bottom Check Allow enabling hardware masked units
Then Checkmark the 2 Bit xx that say disabled
ok.....ur done...restart windows and run a 3D intense program........if it has a lot of artifacts......it didnt work and u have to change back.....
HOPE I HELPED
The above was quoted from another member on the forums. He sent this to me via PM. Now, I have heard problems about 128mb guys doing this to their cards, i have a 256mb DDR3 on my card and it worked wonderfully. just remember exactly what two items you check, so you can go back and uncheck them if the cards goes out of whack. i also overclocked using the tools that ASUS had given me with the card. I have my card running at 420mhz and its DDR3 @ 1.1ghz with the softmod with aircooling. I have quite a few case fans and have no PCI slots taken up. The 3DMark05 score i get is 5,052, so with this mod, you can hand with the best of them.
The link must be outdated, it doesn't work anymore, sorry guys.