I have been googling for the past 10mintues and it looks like there isn't a soft mod for this card.
However it is not necessarily safer to do a soft mod because you risk corrupting the BIOS......which makes the card useless. Atleast with a hard mod you can erase the pencil and make the mod disappear
If you are wondering here is the hard voltmod Here
And you will also see more performance increase with a hard mode because it allows more volts.
Also on a side note, there are not many cards that i am aware of were you can actually increase the voltage through the BIOS. Most cards simply don't allow it, that is why there are hard mods.
Good luck with what ever you choose, and maybe someone else knows of a softmod for you.
However it is not necessarily safer to do a soft mod because you risk corrupting the BIOS......which makes the card useless. Atleast with a hard mod you can erase the pencil and make the mod disappear

If you are wondering here is the hard voltmod Here
And you will also see more performance increase with a hard mode because it allows more volts.
Also on a side note, there are not many cards that i am aware of were you can actually increase the voltage through the BIOS. Most cards simply don't allow it, that is why there are hard mods.
Good luck with what ever you choose, and maybe someone else knows of a softmod for you.