2 minutes render time, left CPU and right GPU with high poly mesh 1.9GB data. (6 core Xeon and Quadro RTX5000)
in this cache, the GPU was faster and more stable. its response time on shaders changes not too bad. only sampling changes took 3-4 seconds to respond
.Octane was crashing on this scene while loading the geometry. Blender Cycles needed 4 minutes to load the alembics.
the CPU is much more efficient in cleaning up the final noise than the GPU. the render result is line up on both, but sampling is quite different. it would be impossible to mix CPU and GPU renderings.
In the end, the GPU rendering is a little faster the CPU rendering (once you optimized the render setting.) Optix GPU rendering does not support GPU BVH branching only pure AA samples, that’s properly why I am not getting the excepted massive render speedups on the GPU.
Tests in Blender showed CUDA rendering are faster then Optix rendering (with RTX).