Dang nice. Have you flashed your 56 to the 64 BIOS? I heard they should has about the same after that. And very curious of your power draw per card. I know HWinfo/GPUz is not reliable, but what do they say your cards are each pulling?

Which version of WIN10 did you go with? I've got 4 56's coming tomorrow and setting up win machine (my current rigs are all Ubuntu for RX470/570s) so kinda restarting with my knowdledge base....