hi guys! i am trying to build my own computer and i am fine with my cpu, gpu and motherboard but i am now in my memory ram so, i have a problem because i don't know if every ddr4 memory has the same pin? (you know the hole in the middle of them) please correct me if there is a correct terms for them. so the question is? if i buy a ddr4 memory? is it guarantee that it is compatible as long as a motherboard is compatible to a ddr4 memory? any comment will be appreciated guys! thanks a lot!.