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.
Dual-channel technically doubles available RAM bandwidth and would enable large memory copy operations to complete as much as twice as fast.
In the real world though, applications do a lot more non-linear memory accesses than large and conveniently aligned sequential block transfers (even less so with adoption of 'zerocopy' and CoW programming models) so as people above said, memory bandwidth does not have quite that much of an impact on most software.