Using 4 sticks will require more of a power draw from the controller so that's why it's better to use two sticks. It just may give you better performance by using two sticks. You can see the difference in the WEI if you have both 2 and 4 stick configurations.
Isn't that why the motherboard has a 2nd dedicated power supply for the CPU to provide a better and more constant power draw?
And if they reason that is potentially worse is because of more heat then as long as i have a good liquid cooling wont that compensate for the extra heat and prevent any overheating.
I will try your idea of testing both setups to see if it gives any difference.