Xian, I happen to have 18 myself. What is your solution for powering them? I didn't plan ahead for my shipment all that well, so I currently have 12 attached to a standalone 1000W ATX PSU; the other 6 are leeching off of a different PC's spare PCI-E cables (in a different room altogether). I'd like to consolidate them if I can.
Using a Corsair TX 850 to power 10 of them, and using the PCIE cables off a RaidMax 1000W that is powering the host CPU to drive the other 8 K16's.