Hello dear friends.
I have GA-Z87X-UD3H and I have the same issue for about a week, since i just bought my new PC. So i dd little research on this topic and about this problem. I am not sure if this could resolve the problem but I`ve read about a possible solution since it seems logical, so I hope this help will come useful for anyone else who have this problems.
So if you are using windows 8 / 8.1 (because I do) i`ve read on a forum that exactly windows 8 is making the damn problem. Here is the link:
http://linustechtips.com/main/topic/35694-z77x-ud5h-code-d4/ Shortly, what I`ve tried to do and what help other people to fix this issue is: Try to disable fast book option in windows 8. Why? well since Windows 8 never shutdown even if you go start->shut down, but instead, it goes into some hibernate / sleep mode even though you`ve press shutdown. So here is a link how you can disable fast boot:
http://www.eightforums.com/tutorials/6320-fast-startup-turn-off-windows-8-a.html (this link shows how to enable, but you have to UNCHECK "fast startup". Or start windows "CMD" as administartor and type this "powercfg -h off" (without quotes)
That i`ve tried so I hope it will help you too.
Regards