The 8-pin power has four +12V connections and four ground connections. It IS keyed so that a 4-pin "P4" connector can be connected to four of the eight positions (at one end, I don't recall which ...

There is no 8 pin connector on this power supply or another new Antec 350 that I have! Yes, four of the connectors are capped off but the instructions further read to take the cap off.