Uasage of GPU for VFB while rendering mode is set to CPU rendering - is this possible?

[3d-laboratory]

When the renderer is set to "VRay 5, hotfix 2" the V-Ray frame buffer window or the viewport IPR uses mainly the CPU. If it is set to ""VRay GPU 5, hotfix 2" it uses the GPU. As my render station is a Threadripper 2950x machine with a low cost graphics card I render there via backburner. But on my workstation I have a Quadro P4000, mainly because of my 3 screens. Is there a setting that enables the GPU for the IPR when CPU-render mode is set for the scene?

[hermit.crab]

There isn't such an option. However, some features like Denoiser and Lens effects may be calculated on the GPU (via the Hardware acceleration checkbox), which is activated by default.

[3d-laboratory]

Thank you! Yes, I have seen some GPU activity also with CPU rendering set.