The Corsair 650D has 4 identical pins (see attached picture) that come from the front panel and I don't know what they are for. I have been able to connect everything else, i.e. USB 2.0 cables and front panel LEDs, audio, and power button, to my Asus P8z68-V motherboard, but I couldn't any similar ports on my motherboard.
I have been using my computer for about 2 weeks now and haven't noticed anything missing/malfunctioning. Any ideas what they are for?
Those are to control / power your case fans that came with your case
You plug your three fans into them and use the molex cable to plug into your PSU. This will allow you to control your fan speeds by the button on top of the case (under the sliding hot swap bay).
Ahhh gotcha! So there are 3 case fans and 4 2-pin connectors. I checked the case fans and they plug into the 2-pin connectors so that works. I am assuming there is an extra one in case I decide to switch out my 200mm fan at the top for 2 120mm ones or something... The only problem is that there is no molex cable anywhere...