Z170A Gaming M5 top PCIe 16x slot issues

Which PCIe slot should my GPU be in? 16x pcie slot according to your own link it could sit in either the top slot or the 2nd slot both the same Multi-GPU CFX support 2 x PCIe x 16 (supports pg slot character slots and one x1 slot There is also the C7X99-OCE-F Or if you want the x16 slots to actually be x16

aksitoto slot It's a slot of x16 size but electrically x4 This