So I have one 4GB 1600mhz stick of Corsair Vengeance memory in my ASrock Z77 extreme 4 Motherboard out of the four memory slots I have. Although I never go over 70% usage of my 4GB of memory so do I really need more? I'm planning on purchasing another 4GB and utilizing the dual channel feature of the motherboard. I want to know what it does and how it's different from quad channel. Also what if I just used one stick of 8GB instead of two sticks of 4GB? would I have more performance with the single 8GB stick or with the dual 4GB stick. What does dual channel, or quad channel do.