Crossfire incompatibility: What would happen?

[Ahammer18]

Simple, what would happen if I crossfire'd two incompatible GPUs? The two that I have are the Sapphire R9 280x and the Sapphire HD 7770. Would it just not work, or would something terrible happen?

 

[MarkW]

They would refuse to link (no crossfire).
The main card would be acting like it was the only card in the system.
The secondary card might give you some output ports that work, but the Crossfire would not be there. It might also just do nothing.