Could be a few issues. One could be a bios issue bug. Try updating your bios. On new mb a lot of them are set to boot from the ipgpu first till you go into the bios and swap the primary display from ipgpu to peg....pci. Look for pinched wires or a short in the pc. Make sure the mb not grounding out.
At post watch the led on the mb. The power good led should stay on if it strobing try another power supply see if the error stops.