AMD has released a brand new driver for its graphics cards. According to the release notes, the AMD Radeon Adrenalin 18.7.1 driver is optimized for Earthfall and improves performance by up to 28% on the Radeon RX Vega 56 and by up to 22% faster on the Radeon RX 580.
Source: N4G PC AMD Radeon Adrenalin 18.7.1 is optimized for Earthfall, packs fixes for Hellblade and Fortnite