If you were hoping for a quick arrival of a full Navi-based lineup from AMD you seem to be out of luck as the company is taking its Polaris architecture out for another spin. TechPowerUp writes AMD's Radeon Software Adrenalin 19.4.3 graphics drivers contain references to the Radeon RX 640, a new low-end model based on the aging Polaris architecture.
At this point, it's unknown what's going on here. Will there be no low-end parts based on the Navi architecture? Or is AMD rolling out rebranded Polaris parts as the Radeon RX 600 line, while keeping the rumored "Radeon RX 3000" series for Navi-based parts only? Guess we'll find out more later this month at Computex.
VideoCardz doublechecked the news and also found a Radeon 630 in the Radeon driver files. The Radeon 630 is a rebrand of the Radeon 540X, while the Radeon RX 640 is a rebrand of the Radeon RX 550X.