460 has worked OOTB for some time in Sierra
Just not very fast
Me = not so lucky. I purchased a Sapphire Nitro 460 for my Mac Pro 3,1 - but no boot screen, no boot at all with the Sierra installer.
Got hung up installing Sierra using a Dell HD 5770 flashed w/ Vervet (even starting from a clean install of El Cap. on new drive - can't think what might be the problem other than the 5770 - Ram and Drives seem OK - no other hardware). Was really hoping the 460 would allow me to install Sierra. Was it wrong to assume the installer would load the kexts for basic operation at least?
Old HD 5770
Device ID: 0x68b8
Revision ID: 0x0000
ROM Revision: 113-C0160C-155
EFI Driver Version: 01.00.436
New RX 460
Slot: Slot-1
PCIe Lane Width: x8
Vendor: ATI (0x1002)
Device ID: 0x67ef
Revision ID: 0x00cf
Kernel Extension Info: No Kext Loaded