OK I threw my 750 Ti back in my 4,1>5,1 cMP yesterday (running 10.13.6). First off, it does show the Ti in "About This Mac":
I was unable to get the globaltv site to work due to not being in Canada. And every video I tried on CBS.com just said it wasn't available. However, I get that same message on my 2015 MacBook Pro and it just dawned on me that it's likely due to using PiHole for ad-blocking. I'll try disabling it when I get to work and see if it will play.
I was able to get video playing on NBC.com (one of their dumb reality shows... can't remember which).
BUT... Movies I had bought through iTunes would not play. At first I was connected to a Dell 2407wfp via DVI and was getting the following error:
I did some googling and found some posts about that monitor having potential issues with HDCP over DVI. So I unboxed the new Dell P2715Q I recently bought and connected that to the 750Ti via DisplayPort. Rebooted for good measure and tried to play an iTunes movie again... only to get the same error.
I can't imagine the P2715Q not having HDCP, so I think perhaps it's the card that is not negotiating it properly. Not sure if that's an issue with the card, the MVC EFI mod, or the web drivers. I don't have another NVIDIA card to test (well, aside from the stock GT120).
Does anyone know of a Mac app to test for HDCP compatibility/versions? I know for Windows you can use Arcsoft BD & 3D assistant or Cyberlink UHD Ready (and maybe other tools too) but I don't know of anything on MacOS.
I forgot to try Amazon but will do that later today. I don't subscribe to Hulu so I can't try that.
Edit: I sold my Radeon 7950 already. I have a Sapphire Pulse RX 580 sitting here but am waiting for the power cable to arrive from China. Once it arrives I will test that with the same DP cable/monitor to see if the iTunes movie will play.
It would be interesting if anyone has an unflashed Maxwell NVIDIA card they can try under 10.13.6 with the web drivers installed to rule out anything caused by the MVC firmware.