Which 4 pin EPS connector to use?

[LightSpeedYT]

OK so I'm helping a friend upgrade his pc and he is getting an EVGA 500 B1. That power supply has a 4+4 EPS connector, but his motherboard only needs a single 4 pin connection. I was just wondering if it mattered which of the 4 pins he should use.

 

[dudmont]

Either will work, but the connectors will only fit going in one direction.