Compatible CPU, & the BIOS version required are listed here: http://www.asus.com/Motherboards/M5A97_R20/HelpDesk_CPU/
For the FX-8350 CPU, BIOS version 1006 or later is required.
You can check your board's current BIOS version in BIOS Setup, it will be shown at the top.
If required, you can get BIOS updates here: http://www.asus.com/Motherboards/M5A97_R20/HelpDesk_Download/
In the drop-down box under "Drivers & Tools", select "Others".