This should be the driver for this: http://launchpadlibrarian.net/7382416/L ... er_new.rar http://gentoo-wiki.com/HARDWARE_Asus_F3SV http://forums.gentoo.org/search.php?sea ... 1b7e79fc76
This is some links with extra info you might want to check out.
How-to once you have the driver downloaded and can post what is inside the rar file someone on irc / web chat top right of this page should be able to help you or one of the gentoo forums post in the above link might have the answer.
Sometimes searching for the specific motherboard + linux can help as well with some extra info / how-to for the specific motherboard.
What version of Sabayon are you using ?
Hope this helps.