Sorry to revive this thread but it stills comes up in google so I figured I would add this as it might help some people.
I have a :
Gigabyte Z77X-UD5H
and a
Gigabyte Aivia Osmium keyboard
that I recently purchased. I like the blue back-light on the keyboard, but when I would put my computer to sleep it would stay on, and it is pretty bright so it makes it hard to sleep. Pushing the LED off scroll wheel didn't help, but unplugging and replugging would make it turn off. Obviously this was not a desirable solution.
I searched around but a lot but there weren't many things I hadn't already tried (changes the wake setting in dev mgr). I came here but my BIOS did not have any USB Wake Up From Sleep under power management and F1 now switches between advanced and 3D view so ctrl + F1 did not reveal any hidden options.
Turns out you just have to set "ErP" (stands for Energy-related Products) to "Enabled" in the power management tab, now my keyboard backlight turns off when I sleep my computer, although according to the manual (found here:
http://download.gigabyte.us/FileList/Manual/mb_manual_ga-z77x-ud5h_e.pdfl this mode prevents anything from waking the computer from sleep, including the LAN card. Doesn't matter to me but some might need that.
Sorry to revive this but hopefully it saves someone like me a few hours.