HD 7870 crossfire on GA-Z77X-UD5H?

Winchester976

Honorable
Aug 5, 2013
4
0
10,510
As i know first PCIe slot on this motherboard is x16 and second slot is x8, when i go with crossfire both slots it's gonna be x8, correct me if i'am wrong :) How will crossfire work on both x8 slots?
I have i5 2500k...