Yeap, it's fake, also rx 480 have never done over 22Mh/s in eth.
23-24 perhaps with a stock BIOS on the 8GB cards with their faster RAM, higher needed modded BIOS with memory timing changes.
I was seeing 21-22 on STOCK bios on my Sapphire RX 470 4GB "reference" type cards despite the slow RAM.