I might have explained myself the wrong way, but what you said does not contradict anything of what I said. The mobo+cpu will support any sticks, as I said, although not natively, you will have to overclock.
And you also suggested a lower freq set of ram, the same thing I did.
I did not check that the z4000 only came in sets of 2 and no quad channel, that was an important oversight from me.
We are both of the same opinion, there was no contradiction
Also, I believe that application is really important, some uses are more sensitive to memory speed than others. For gaming, I think a 4000 set is unnecessary.