I have an empty scene with a SceneCaptureCube actor set to capture every frame. I get really good frame rate (90fps) in the editor for DX11 but not for Vulkan/DX12 (50fps). The performance difference gets even worse for a populated scene, e.g. DX11- 40fps vs Vulkan 1fps.
Profiling using Unreal Insights shows that there is significant time being spent on memory allocation which is not present in DX11. I have attached screenshots of the frames for each. I have noticed that reducing the shadows from epic to low in scalability settings improves the fps significantly to match DX11 performance. DX11 also uses ~3GB less VRAM compared to Vulkan/DX12. I’m thinking it’s something to do with VSMs.
Is this a bug? I need the SCC in Vulkan to work comparably to DX11 with realistic shadows.
System:
UE 5.1, 5.2
Graphics: 3070 laptop 8GB
DX11
I have RHI thread enabled as it gives better performance.
Vulkan
DX12