The only reason why anyone would want to use two 12V-2x6 cables is to have a PC with two Nvidia graphics cards but given that SLI is dead and long gone on the latest generation of GeForce GPUs ...

It has the 12-2x6 power cable as standard, no adapters required. That should have made it easier to plug the cable in correctly. At this stage, it's not clear whether this is the user getting ...