Question about ASUS 970 Pro Gaming Aura

Basically, any graphics card will work with this mainboard. PCIe 3.0 is downward compatible with PCIe 2.0.
Please note when purchasing a graphics card:
- Sufficient 6/8-pin power plugs available from the power supply unit?
- Sufficient power available from the power supply unit (e.g. if the graphics card requires 250 watts, the power supply unit should be able to deliver approx. 550 watts).
- Does the graphics card fit into the case (length / size)?

Depending on the application / game, the CPU / PCIe 2.0 can limit the performance. Therefore, in my opinion, it would not be worth buying a high-end graphics card like the "GTX 1080 Ti".

Only relevant for gaming:
If you have a screen with GSync technology, it is best to buy an Nvidia graphics card. If you have a screen with FreeSync technology, buy an AMD graphics card. If your screen does not support either of these new technologies, the decision is yours.

To compare the effective performance of graphics cards, I can recommend the site userbenchmark. In the following link you can see a comparison between AMD RX 480 and Nvidia GTX 1060 6GB: http://gpu.userbenchmark.com/Compare...

What kind of games and in what resolution (monitor(s))?