If your motherboard comes with the “thermal back-plate”, ex. Gigabyte x570i Aorus Pro wifi and B550I AORUS PRO mini-ITX, please remove the “thermal back-plate” from the motherboard first, then you will be able to install the PCI-e Riser cable into the motherboard. Since the back-plate is thicker than the motherboard and leads in contact with the riser cable, so the riser cable will become too short to install. Or you may consider to purchase the 180mm PCIe Riser cable instead