This is not an unusual move, though perhaps disappointing given that Vega is the newer and more interesting GPU architecture at this point. The Radeon RX 500X also represents the third round of Polaris, only this time it does not appear that AMD has made any architectural optimizations. According to AMD, the rebranded effort is aimed at ensuring the company's OEM partners are using the latest hardware.
"There are no hardware differences to non-X [RX 500 GPUs]," an AMD spokesperson told PCWorld's Brad Chacos. "The Radeon RX 500X series graphics cards is a brand refresh for 2018 OEM platforms that ensures Radeon RX 500 series cards are using the latest ‘Polaris’ architecture-based hardware and driver revisions (Radeon Software Adrenalin Edition) for 2018."
AMD's statement suggests that the Radeon RX 500X series will only be available to OEM and boutique system builders, rather than being sold directly to consumers. The takeaway is that if you already own a Radeon RX 500 series card, it is still just as good as the rebranded cards.
That also means the specs are the same across the board, save for the Radeon RX 550X. For whatever reason, the rebranded version sports a faster clockspeed—the GPU runs at 1,287MHz, versus 1,183MHz on the Radeon RX 550. Otherwise, the specs are the same everywhere else, including clockspeeds, the number of compute units and stream processors, memory configurations, and so forth.
Look for the rebranded GPUs to show up in new and upcoming desktop and laptop models. If nothing else, their presence in a system configuration is an indicator that it is using the latest hardware, Performance wise, however, Radeon RX 500X GPUs should perform the same as their non-X counterparts.