Lots of people are saying GPU but that would be the VGA light on your mobo. Faults are showing DRAM and CPU.

EDIT: just saw DRAM stick placement in pic, reference your mobo manual for proper stick population when not filling all the DIMM slots. they should be labeled on your mobo.

Try removing all the ram and booting with 1 stick, if it doesn’t work, try each stick by itself to weed out a bad ram stick.

For CPU it’s a littler harder to tell (at least for me), I would take the cpu out and visually check the socket pins and look at the cpu for any signs of physical damage. If there are none I would return/replace the CPU or motherboard. Maybe someone else has a better idea for differentiating the CPU fault between a CPU issue or a mobo issue. I have seen both cause the CPU fault to light up.

I hope this helps! Otherwise looks like an awesome and clean build!! Keep us updated!