confusion about PCI Express x16 labeling and slots

[relikpL]

For instance, my MSI 870-G45 supports PCI-Ex16 x2, but PCI-E Gen2 has support for 1x16 and 1x4. This is according to MSI's website:
MSI Global ? Computer, Laptop, Notebook, Desktop, Mainboard, Graphics and more

Does this mean that one PCI-E slot is capped at x4, whereas the other is x16? How would crossfiring video cards work in this scenario?

Appreciate the help in advance.

 

[Muffin Man]

yea, that board has 2 pci-e slots, one will operate at full x16 speed and the other at x4 speed. you could still crossfire two cards, but the second card will be somewhat bottlenecked because of the capped speed of the slot.

 

[relikpL]

so it doesn't really make sense to crossfire with x16 and x4, or is the performance loss minimal? I read some article that claimed it was only about 5% vs x8.