Uhm, I suspect the Original Poster means the power supply has a 4 pin meant to plug in near the CPU, and lacks the additional 4pin meant to plug in exactly adjacent to the 20-pin.
I think the extra pins are additional copies of the same supply voltages, but don't know enough about how they are paralelled on motherboard or power supply to predict whether it is just a matter of degraded capability compared to the intended type, or something worse.
Not ideal, that much is sure.