Basically on a motherboard like H8DME-2, can you use all memory sockets if you have only 1 CPU installed? Or are each memory "section" per CPU? (not sure what they are called)
I do believe modern processors have their memory controllers on die, so this makes a lot of sense. Even if it didn't, it would be a lot more complicated to share ram between processors rather than to have each processor handle its own ram. I believe the necessity to have the same amount of ram per processor is because the system uses SMP without a shared system bus (the alternative being NUMA, which opterons support).