I am wondering to know if it is compatible with Vulkan specilly using X-Plane 11. Thank you for your help and your support.
according to TechPowerUp website for the specs on the HD 5850 it doesn't support Vulkan API: ATI Radeon HD 5850 Specs | TechPowerUp GPU Database
The reason why is because AMD doesn't support that GPU with Driver updates anymore. Thus you only have a choice of two last AMD Drivers for that GPU card (2015 & 2016) unless the manufacturer of your GPU card has newer drivers.
EDIT: Vulkan is enabled by the GPU driver. Vulkan wasn't part of the AMD Driver yet in those two drivers.
AMD Radeon Software Crimson Edition 16.3 and later support the following AMD APUs and Radeon™ GPUs1 based on the Graphics Core Next architecture on Windows® 7, Window® 8.1, Windows® 10, and Linux®
The HD 5850 is still respectable but the card is older and VULKAN is far more demanding than what older cards can handle.
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