RADV vs. AMDVLK vs. Radeon Software Vulkan Driver Performance - October 2018 Linux Gaming
AMDVLK had advantages over RADV for Rise of the Tomb Raider while the PRO driver was delivering even greater performance. The Radeon RX Vega 64 when using Linux 4.19 was hanging when running this game but didn't encounter that problem with the other drivers.
Serious Sam 3 BFE saw RADV outperforming AMDVLK but the PRO Vulkan driver was delivering comparable or in some cases superior frame-rates.