The motherboard is tri-channel with a less-than-optimal dual-channel fallback capability. You'll notice that all the tri-channel configs are evenly divisible by three. Since the 8GB configuration comes with 4x 2GB DIMMs and there are only six slots, you'll hit a max of 12GB if you don't want to "waste" any of the memory that came with the computer. You need to have triplets of the same size, for optimal memory performance. 16GB is sub-optimal.

I can explain it to you but I can't understand it for you.