This simple setup doesn’t work in V-Ray GPU:
Any procedural map (checker, noise etc.) doesn’t work when connected to input of OSL map.
I think you need to plug the “Out” output into the diffuse map. Otherwise, this setup does not seem to work in IPR GPU only, production rendering works fine. Most likely due to OSL maps not having full support on V-Ray GPU as stated in the documentation.
“Out” output doesn’t work either…
So - this is not a bug?
I seem to get identical results with the mentioned setup on both CPU and GPU. Which V-Ray version are you using? Also, try updating your GPU drivers to the latest recommended one. Do attach the scene in question here or send it via the contact form so we can take a look. Mention this thread in the message.