I don’t think anyone expects that a good Vulkan renderer gives significantly better performance than a good DX12 renderer, they should be roughly equal. The PC DX12 renderer in UE4 is far from ideal though, so I guess you mean you expected that the UE4 Vulkan renderer would be better than the UE4 PC DX12 renderer? I think that will definitely be the case on PC at some point, because there’s no point in doing any DX12 related work on PC any more when you have Vulkan that works pretty much everywhere. The Vulkan code in UE4 is still way newer though, so I don’t expect it just yet.