V-Ray for Rhino shows full PNG transparency on CPU, but not on GPU

[Bar_Wolpert]

Hello all, I’m trying to render this image, and it’s only fully transparent when using the CPU, which I understand is much weaker. What can I do?
Thanks a lot:)
ignore that the png is upside-down

[Micha]

Your background isn’t transparent?

Or did you mean you want to get a transparency in reflection and refraction? If this is the case than try an other “affect channels” mode. First enable advanced settings per slider icon on the top.