Planning to renew my trusted macbook pro after five years I am tempted into the new Vega Pro cards because of their graphics speed. What can be gained with Vray sketchup pro here? (and Windows is not an option… 
You won’t be able to render with it, because currently we support only CUDA (NVidia).
Apple has also deprecated OpenCL earlier this year.
It still can be used for the V-Ray denosier and lens effects, but you will be just fine with enter class GPU for denoising.
Best,
Blago.
We will have to find another comparable solution then, because such a singleminded rendering option will slow down our workflow way too much with all the added costs in lost hours in waiting or through machineswitching.
The only raytrace engine that I know that can run on GPU on macOS with the only official API for macOS (Metal) is ProRender from AMD, but it is not available for SketchUp.
For Linux and Windows, due to CUDA being supported there are much more options.
We support CUDA on macOS still, but Apple doesn’t give NVIDIA as an option at the moment. We will support other GPU rendering solutions on macOS as soon as there are production ready APIs and hardware for it.
Best,
Blago.