Aurora R12, backwards compatible GTX 980?

It's not fully compatible with windows 10 versions higher than 1709 by the looks of it.

GTX 980 

Looks like windows driver support is EOL for that model, and the older driver might or might not work on the latest edition of windows 10.

NON Dell cards require secure boot OFF in bios or it wont post.  The not fully compatible is a red herring.  Legacy cards will not be detected and auto installed if the most recent drivers for Pascal/Turing/Ampere and later cards are installed. Other than those issues it will work fine. NVIDIA stopped supporting older cards 7 years ago.

NVIDIA and ATI and other vendors made a cutoff for specific drivers for older cards. The change they made in 2020 was to drop 32 bit support and Legacy support.

No XP/VISTA/7 drivers for newer than pascal and no 32 bit drivers for ANY card.  Everything is WIN10 only 64 bit only period end including linux drivers being 64 bit only.

That is also why a Radeon 5450 for example wont seem to work.  If you manually install the WHQL legacy driver it works fine all the way down to legacy HD 1000 2000 3000 4000 series cards that are max DX10 cards.

https://nvidia.custhelp.com/app/answers/detail/a_id/3156/

Older NVIDIA cards also work fine in newer models once the correct supported whql driver is installed. 400 series drivers DO NOT Work for these older cards.

https://www.nvidia.com/download/driverResults.aspx/86510/

Only the PCI-E 1.X cards will be a problem

Ancient cards like 8800 GTS etc.

If you mean Aurora-R2, probably not as I think that is a non-UEFI system. If that is true, then video-card will likely not be incompatible. 

If the GTX-980 is after-market, it might have a dip-switch to select between Legacy-BIOS and UEFI.

"It's not fully compatible with windows 10 versions higher than 1709 by the looks of it."

That's an old thread about people who encountered issues upgrading from windows 7 to windows 10 when it was fist released.  If you go to Nvidia's official website they offer Nvidia drivers for the GTX 980 with windows 10 available to download. 

"NON Dell cards require secure boot OFF in bios or it wont post."

How can I disable secure boot if I can't see the BIOS screen? I installed a Dell RX 580 in a newer R12 Alienware and cannot see the BIOS, though the machine boots perfectly into Windows 10.

Is there a way for it to work with a 1060? I disabled safe boot and whql doesn't work with it since it is already works with windows 10, I can't get the 1060 to show anything on the R12

I bought a new R12 with no GPU and am trying to get a NVIDIA GeForce GTX 1070 Ti - FE Founder's Edition 8GB GDDR5 Graphics Card to work in it.   installed the card and plugged in the 4 prong and 2 prong power connectors into the 6 prong card.  When I try to power on the PC, it won't even light up the power button.  If I unplug the card, it powers up (but with no GPU).  How do I get the 1070 ti to work in the R12?

The power button not lighting up is a bit odd and could indicate an issue with the video card, but for a non DELL card to work you need to turn off secure boot in the bios. For that you would need a card that works first, so it is a bit of a catch 22, since there is no way to turn off secure boot when you have no display output.

I would test the video card in another system to make sure the card is not faulty.

Ok, this is weird to me, but I'm new to this stuff. I unplugged the 6 prong and 2 prong power cords from the GPU. I had the 6 prong on the right and the 2 prong on left. When I put it back with the 6 prong on Left and 2 prong on right, it powered up and is working.
Thanks for the replies, all is working

Glad to hear you have it worked out. Normally those connectors are keyed so you cannot plug them in the way you originally plugged them in without really forcing them down.

Good it caused no damage, and it looks like you are all set now.