Comment 7 for bug 1007508

Your attached dmidecode.txt says

BIOS Information
 Vendor: Award Software International, Inc.
 Version: F5d
 Release Date: 10/21/2011

According the Gigabyte web site
http://www.gigabyte.com/products/product-page.aspx?pid=3754#bios
most recent BIOS for GA-870A-USB3 (rev. 3.0) is F4 (2011/03/09)

According the Gigabyte web site
http://www.gigabyte.com/products/product-page.aspx?pid=3788#bios
most recent BIOS for GA-870A-USB3 (rev. 3.1) is F5g (2012/04/30)

I assume your motherboard is revision 3.1, but if you haven't already done so you should verify this.
http://www.gigabyte.com/support-downloads/faq-page.aspx?fid=864