Question Trouble with brand new RTX 3090

Nov 24, 2020

I have a nuisance and hope to find an answer to this very expensive issue..
I run an old, but not obsolete system with P8P67 Deluxe w/ i7 2600K @4.4GHz with 32 GB DDR3 and a 1000w Seasonic PSU.

Today my new RTX 3090 arrived and I began installing it to discover that it will not send signal to any monitor, it will however boot into windows without any issues. I've verified with multiple HDMI cables, multiple PCI power cables, tried to re-seat the card multiple times. All to no avail; the buzzer says 1 cont. and 3 pings telling me there's something wrong with the GPU. Is it bricked? I go to a workshop to have it tested.. On a newer mobo with a 500w psu they managed to make it work, then on an older, same-socket as my own, they also manager to make it work but it gave off buzzer warnings too. The card loaded in bios though. The mobo they used was PCI 3.0, mine is PCI 2.0, the card is PCI 4.0. I was under the impression that PCI cards were backwards compatible and that this was no issue.

I'm basically stuck with a brick now until I get a reply from Gigabyte. What do you guys think? Did I make the big dumb and bought a card too powerful for my motherboard or am i stuck with a half-baked fry?