MSI RX 470 4GB modified BIOS: 81 Sols/s on SilentArmy v5 latest on Unbuntu 16.04.1 LTS headless.
Running 6x for 490 Sols/s at 650 Watts.
@mrb and @cryptomined (for the helpful vids)
Full details: Amazon.com 6 x RX 470/480 4/8GB GPU Mining Rig Shopping List - DIY