Fan only Y adapter or regular 4-pin cable?

I realize this may be a stupid question... I am in the midst of putting together my new system, connectiong my Antec 180 fans to a Asus PW5 DH MB. Baffled by the HX620W's Fan Only Y adapter. Should I use that for the 2 Antec 120mm TriCool fans (top and rear)? I realize I connect that to a regular 4-pin connector. Or should I use the "regular" 4 pin peripheral power cables, not bother with the Y Adapter Or does it not matter?

 

Does it matter which rail I plug into?

 

(I assume the " 4-pin peripheral power connector cables" are what are commonly referred to as molex power connectors...true?

 

Also, the User's Manual is rather cryptic, if not skimpy. I've searched for more information about the connectors, no luck. If not Corsair, is there a review site that fgives more detailed about which connectors to use, which rail to plug them into, etc.?

Molex is a company that makes all types of connectors, including the 4-pin peripheral power connector cables, so calling them Molex cables, while accurate, is also not very specific, as they make SATA connectors and fan-header connectors as well.

As for whether or not you should use the Y-adapter, that's up to you. It certainly won't hurt to use it, and it allows you to use 2 fans off of a single 4-pin connector, so I use it on my systems. However, it is not necessary, and nothing bad will happen if you don't use it.