Question on the EATX12V connector
here you go :) alot of these connectors just add extra ground pins with a "sence" circuit of some kind on the part in question. I have used 8 pin pci-e as 6 pins as an exmaple by letting the 2 extra pins "hang" without an issue. But yeh, sometimes things do not always work as one wants, all things are not built the same way of course(though there is specs, alot of makers do not always follow them as they should example-80 plus certification)