Change the MB to Gigabyte GA-970A-UD3P for your FX8320. Also I recommend get other cooler like hyper evo 212 instead the tx3.
For the fx8320 you don't need to update the BIOS.
PCPartPicker part list:
http://pcpartpicker.com/p/3FKVTW
Price breakdown by merchant: http://pcpartpicker.com/p/3FKVTW/by_merchant/
CPU: AMD FX-8320 3.5GHz 8-Core Processor ($136.48 @ Amazon)
CPU Cooler: Cooler Master Hyper 212 Plus 76.8 CFM Sleeve Bearing CPU Cooler ($25.99 @ SuperBiiz)
Motherboard: Gigabyte GA-970A-UD3P ATX AM3+ Motherboard ($76.98 @ Newegg)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-2133 Memory ($109.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.30 @ Amazon)
Video Card: MSI Radeon R7 250X 1GB Video Card ($77.99 @ SuperBiiz)
Case: Fractal Design Define R5 (Black) ATX Mid Tower Case ($89.99 @ NCIX US)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply ($44.99 @ NCIX US)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($14.98 @ OutletPC)
Total: $626.69
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-04-23 13:55 EDT-0400