Yikes! Your mainboard has some fancy features.
Do you have an option in BIOS to force output?
According to your mainboard's manual http://dlcdnet.asus.com/pub/ASUS/mb/LGA1155/P8Z77-V_LX/E8533_P8Z77-V_LX.pdf you can overclock iGPU.
Disable that and try again.
Go the Limit with iGPU Level Up!
Otherwise disable Crossfire and Lucidlogic support if you have no discrete GPU.