Have you tried to update the bios? F21 is the only bios that works for me, anything over that causes my PC to reboot as soon as it loads up...
I believe the culprit to be Corsair LPX Ram, the gigabyte boards does not like it if you have the 8 gig sticks, another user posted the same problem with the same ram, he then changed to Kingston Hyper X and the new bios worked fine.
For me this board was a bad investment, always supported Gigabyte, may return to Asus for the next one...