Probably 4U PCI-E expansion chassis to one main motherboard.
Six units stacked on top of each other. They have redundant power supplies.
Power in China is $0.03-0.04 kWH.

http://img02.taobaocdn.com/imgextra/i2/292609051/TB25V2KbpXXXXXWXXXXXXXXXXXX_!!292609051.jpg

http://www.cyclone.com/images/headers/products/600-2710system_apr12.jpg