On most motherboards, there are 4 slots, usually separated into 2 colors or 2 pairs of slots. When you only use 1 stick of ram in any one of the slots, it's single channel. but if you use 1 or more sticks of RAM of any of the other slots, it's dual channel. Now pretty much goes the same if you are using a board like for the newer i7. you have three sets of RAM slots for RAM, and if you put a stick in each of the three sets of slots, you are now running triple channel. It's actually a little bit less confusing because you can't run single channel or dual channel. You can only run triple channel. Make sense?