X58, circa 2010. BIOS, no UEFI, PCIe v2 slots.
My VII shows BIOS and POST but posts a black screen before entering either Windows or Linux's GRUB (and, on Linux, I'm on the 4.20 kernel with the vega20 firmwares in my /lib/firmware/amdgpu/ and have the xf86-video-amdgpu package installed).
I'm wondering whether the card's DOA (but why would it work in BIOS?) or my chipset's too old (although cards as new as the Nvidia 1080 Ti work with it, for what it's worth).