I have a Gigabyte 790X board, so I don't know if this applies to your BIOS, but on mine, it's under the Tweaking section and shows up as "CPU NB Vid Control". There is also an ability to show advanced BIOS settings by pressing CTRL-F1 at the main BIOS screen, so perhaps on your board it only shows up in an advanced menu. Wish I could tell you for sure, tho'!