New pc

[Tammam]

I want make pc with 3 graphic card and 1 black Blackmagic Design DeckLink Quad 2 for resoulume arena What is the best motherboard?
For graphic card what the Best
RTX 3090 or Quadro 6000

Thanks for helping

[Arvol]

3 GPU's?
What is your output configuration suppose to be? How many of those outputs connect to the same seamless screen? (To understand if Tearing will be an issue for your setup or not).