I received my Sapphire RX 480 Nitro+ (4GB) GPUs yesterday. Is there also a ROM that I can use?
Without any modification I get ~22MH/s while mining ETH.
You can easily mod it yourself a little bit +2to4mhz. Save your bios rom with Atiflash and open it with PolarisBiosEditor. In the TIMING section copy 1500mhz strap(long code) and replace 1650, 1725, 2000mhz straps. Save and write new bios.