A Closer Look
Gigabyte's thermal solution uses four double-length heatpipes which make direct contact with the GPU surface. This part of the heatsink also cools the voltage regulation and memory chips as indicated by the white thermal pads.
The metal backplate protects against damage during installation and handling. It also provides a little bit of cooling (note the white thermal pads).
Gigabyte is using a 6-pin and a 8-pin power connector. This input configuration is specified for up to 300 watts of power draw.
AMD CrossFire has been running over the PCI-Express bus for a few generations now. The Polaris Series is no different.