Some ram is reserved for a small windows file in windows 7; some is reserved for the onboard video. Dual and tripple channel is determined by the motherboard chipset and which ram slots you use to run your system. The ram really has nothing to do with it; it's all the same; either non-ecc for desktop or sometimes ecc buffered (or registered) which only works in specific server boards and won't even post in most regular desktop motherboards. You don't need to understand the engineering concepts, simply select the proper ram and slots for your specific motherboard. Crucial provides it's own configurator software. I can't explain all the specifics, so if you don't understand the wiki article, then I won't be able to explain it either.