I have an X470 and an X570 so I have options.
In principle I could run 2 or even 3 cards with one of these boards but dual cards is more mainstream
I read a bunch of reviews and mostly the cheaper 4GB cards were tested while the flagship 8GB cards did not hit the radar.
The Sapphire Nitro+ RX 480 8GB is factory overclocked and its not such a bad card even today. The GPU lives on as the RX 580 and probably in yet another rebadge soon. No big deal.
I was not able to see how well the 8GB card fared vs uppity pascal cards. A pair of RX 480s is not hurting.