Hi,
You'll probably find that Loadline Calibration does work in the Avanced Bios settings as well.
In Advanced Settings menu -> MIT -> Advanced Voltage Settings -> 3D Power Control -> Vcore Loadline Calibration and have it highlighted.
Then hit Caps Lock on your keyboard and type EXTREME and hit Enter on the keyboard.
Above method works for the values: AUTO, STANDARD, LOW , MEDIUM, HIGH, TURBO, EXTREME
You may ask why I say hit Caps Lock on your keyboard before typing the word..
From what I found if you don't use capital letters to type the word then the bios turnicates the word and it will default to a different setting.
eg: once I type in lower case "extrem", the next "e" will turnicate the word and there will be only "e" in the input box.
I'd say a bios bug in the gui side of things that gigabyte hasn't noticed yet or haven't bothered with.
To be truthful you'd think that the the Vcore Loadline Calibration input box would be a dropdown box with the options to select the setting.
That would be the method for common user logic imho.
Cheers