Originally posted by: Rike
It's fairly easy. Just make sure you find a good guide. The volt mod will mean that the chip will run hotter all the time. If you have the means to cool it, that's no problem. (That Zalman VF900-cu should do a fine job.) You might get another 50-75 Mhz out of the card, more if you're lucky.
Edit: Here's a guide.