taken from gigabyte forum with some1 same problem as you
I had exactly same issue with my GA-Z68XP-UD3 and i5-3570K. The problem was the old BIOS version, which didn't fully support IB CPUs, so I had to flash a new one. You can't do this with your CPU, because it keeps rebooting and you are not able to start the Q-Flash. You need to get a SB CPU and then flash a new BIOS. The BIOS version you need for your new CPU is at least "FC" in your case, so check the version you have. Be sure to reset your BIOS after the flashing and then load optimized values. It should be able to boot up with your new CPU properly then
that was some1 telling him what 2 do