Asrock radeon rx 580 8gb phantom gaming D OC or Sapphire radeon rx 580 8gb Pulse? I can see the later's(4gb version) performance on gamedebate but i can not find the Asrock one on that site
Even I've Never heard of that brand before. Looks like a local cheap brand, without much reputation, and chances of getting a fake GPU are also high. Do NOT fall for dodgy products. Go for reputed GPU brands, who will also give you proper warranty on the card as well.
i don't think it will be fake(sold by top plus seller) but i agree that the card itsself is almost certainly.. not of the highest quality so i'm not gonna risk it.