Crossfire RX480 with my mobo?

[Vish Petrol]

Hi I have an AsRock H77 pro 4 m motherboard, could I run the RX480s in crossfire on it, or do I need another mobo?
I have the RX480s on pre order, and a gtx 1070 being delivered soon, and want to compare both on my dell U3415W

 

[xb8browney]

Yes, I can't see why not. (2x rx480)

 

[Vish Petrol]

It says that one lane would be at x4, and the other would be at x16. Would that make a big difference?