Vulkan vs what? DX9 or DX11 or DX12. Also it really matters how well you wrote your Vulkan layer. If you write a good DX12 layer and a good Vulkan layer I think

Vulkan vs what? DX9 or DX11 or DX12. Also it really matters how well you wrote your Vulkan layer. If you write a good DX12 layer and a good Vulkan layer I think they will be comparable in perf - The bottleneck will be the GPU and/or driver. So it also depends on how well the driver writers did.