Note: I rendered the same scene using the CPU and also the GPU, and I observe that: the GPU does not render the bevel (bump) effects on the logos; the refraction highlights have different intensity.
Nice toothbrushes I just want to point out that the GPU is a completely different render engine from the CPU and results of both engines are expected to be different.
Some core algorithms are different between both engines and with same settings they cannot produce the same end result.
However the GPU has no problem rendering bumpmaps, so you should be able to get the GPU to render the bump properly (if you tweak the material settings accordingly).
Same applies to refraction highlights.
I thought that GPU and CPU should give the same render output. Then I was wrong.
But then, if it is like that,… how does VRay Next work for the hybrid rendering using CPU’s and GPU’s? Is it using the same GPU algorithms but executing them (CUDA emulation) on the CPU?
Yep! Exactly that! When running in hybrid, the exact same GPU code is run on your CPU so the final output is exactly the same. Basically it’s runnig VRay Next GPU on your CPU