Hello. I'm new here. Need your help guys. Here's what are bugging me: How can you tell which slot to use for each cards? Are there any criteria? What are these 5v and 3.3v for PCIe? And why is it important? Also there are these 33bit and 66bit? What are these and their importance? And these x1, x4, x8, x16 PCIe, I already know that simply speaking, those numbers represent the numbers of data lane connection of the slot, but I don't really know what are their specific differences.