You will need to download the F3 or F4 Bios version
from here
http://www.gigabyte.com/products/product-page.aspx?pid=4305#bios
Make sure that the mobo revision number is the same.... otherwise choose the right revision number.
Another thing before you put the FX8350 into the mobo, you need to update the BIOS using the older processor that you already have inside.
Here's a little read from the manual : (Page 23)
1) Q-Flash allows the user to quickly and easily upgrade or back up BIOS without entering the operating system
2) @BIOS is a Windows-based utility that searches and downloads the latest version of BIOS from the Internet
and updates the BIOS.
And here's from the website....
"Hybrid EFI Technology combines the benefits of GIGABYTE's mature BIOS platform including stability and compatibility with 3rd party products with 3TB+ HDD support from EFI technology, allowing GIGABYTE to offer the best of both worlds through a quick and easy BIOS update using GIGABYTE's @BIOS utility that is freely available from the GIGABYTE website.
GIGABYTE DualBIOS™ is a patented technology that automatically recovers BIOS data when the main BIOS has crashed or failed. Featuring 2 physical BIOS ROMs integrated onboard, GIGABYTE DualBIOS™ allows quick and seamless recovery from BIOS damage or failure due to viruses or improper BIOS updating. In addition, GIGABYTE DualBIOS™ now supports 3TB+ (terabyte) hard drive booting without the need for partitioning, and enables more data storage on a single hard drive. "