I have never watercooled a GPU. I am wondering about these GTX 670s and the thing that is worrying me is, which ones use the reference PCB? I assume that gpu waterblock manufacturers develop blocks that will work on reference pcbs, so that means that I need a 670 that has a reference pcb. This is confusing, because how do you tell, and there are so many that claim to be using the 680s pcb??? I have my eye on the gigabyte windforce 3 fan one, but which one of these 670s uses the reference 670 pcb, or at least the reference 680 pcb?