* The PCI Express specification says this pin must be left unconnected. However, the EPS12V specification says this pin must be used for +12 V (yellow wire).
† The Sense0 pin generates a code for the video card to know which kind of power connector is available. When this pin is grounded (black wire) and the Sense1 pin is not available (which is the case), this indicates that the auxiliary power connector is a six-pin one. Therefore, six-pin connectors have this pin grounded.
PCI Express 8-Pin Auxiliary Connector (PEG)
† The Sense0 and Sense1 pins form a code that tells the video card which kind of power connector is available. When both are grounded (black wire), this tells the video card that an eight-pin connector is used. This is the reason why on eight-pin connector pins four and six are grounded.