I think something is wrong with your RAM configuration... none of your memory is paired, it's all single channel!
Channel A B should be populated completely while D and C remain empty.
I dunno, give it a try, I just would never have installed RAM like that from my experience (which is building over 3,000 comptuers and having just build a system with this motherboard)
Not the case for 4-channel. Each channel is populated with at least one module to make use of 4-channel memory. The OP's memory is setup correctly.