PhoenixMiner
I have 2 GPUs on a RIG. One - RX470, One RX480. Drivers 18.11.1
Miner says:
2018.11.27:13:12:49.984: main GPU1: Radeon (TM) RX 470 Graphics (pcie 1), OpenCL 2.0, 8 GB VRAM, 36 CUs
2018.11.27:13:12:49.984: main GPU2: Radeon (TM) RX 470 Graphics (pcie 1), OpenCL 2.0, 8 GB VRAM, 36 CUs
2018.11.27:13:12:49.984: main GPU3: Radeon (TM) RX 470 Graphics (pcie 4), OpenCL 2.0, 4 GB VRAM, 32 CUs
2018.11.27:13:12:49.984: main GPU4: Radeon (TM) RX 470 Graphics (pcie 4), OpenCL 2.0, 4 GB VRAM, 32 CUs

Mining Speed low... 11Mh per card...