I’m attempting to upgrade my Mac 2012 12 core ‘cheesegrater’ with a Radeon RX580 graphics card. I have a Protools HDX card installed that uses one of the internal pci power supplies. I was advised to purchase a Corsair RM 650x external power supply for the graphics card which requires both internal power connections. I don’t seem to be able to find the correct cabling to connect the graphics card to the external power supply. Any help would be appreciated. Thanks