Hello,
How can a MacPro 5.1 (2012) recognize a Radeon VII ?
Other GPU (RX 560, RX 580, RX570 ...) are well recognize, but not this one ...
Best regards
They were launched without a UEFI BIOS. That may be the problem. You need to download and install a UEFI BIOS for those GPU. Do not flash them from within Windows. Use a USB stick method. And good luck, if it goes wrong you might brick your GPU.