Ok guys,
Thought I would give an update with the gigabyte support. After lots of effort, they finally managed to reproduce the problem (Needed to ship my usb stick to them). However, they don't quite know the reason, it look like it's an incompatibility issue with the stick.
Since i'm not the only one (lots of people here) I think it's a problem in their design.
The only thing they offer me was that they could send it off to their main engineering team for futher investigation. At this point, it's already been couple months that they working on it and I'm giving up.
Moral of the story is that they seem to have some incompatility issues with some usb 3.0 devices and the z77x-ud5h board and even them, they can't come with a clear answer to me.
I'll be swtiching board as my assus one doesn't have this issue. Tired of waisting my time with them seriously...
Thought I would give an update!