So since Apple/AMD don’t release a new openCL driver, OpenCL rendering it won’t work properly, right?
I don’t know the current status, both the Cycles code and the drivers are changing on a regular basis. Cycles on AMD GPUs is a very long story without a happy ending. My impression from reading the other threads on AMD hardware is that it is working rather well on Windows by now, but I haven’t read anything from Mac users lately. Just try it. If there’s a problem, chances are you’ll have to try again later.
Another complication is that rendering kernels are compiled depending on the features you need, so using certain features may cause compilation to fail while in other cases it might pass. I’m not aware of this being documented extensively anywhere (ideally it should work in all cases).
Let me also fit in a grievance: Apple’s support for graphics/compute APIs (OpenCL/OpenGL) has been terrible for many years now, just like their misguided decision to exclusively ship AMD hardware with their own drivers.
NVIDIA hardware is actually supported fairly well (by NVIDIA), but (aside from old Mac Pros) the only way to use it is somewhat costly external PCIe adapters. That may or may not be an option for you.
At work I have a MacPro (not the new one) with a GeForce GTX 1080 with 4Gb
I’ve never heard of such a model, 1080s are supposed to have 8GB. Maybe it’s a 980?