I have to make some assumptions here:

The mobo has PCI slots,
probably 4 or more,
these are PCI cards.

Mobos have one or more bridge chips. The bridge connects the CPU to a PCI bus. A bridge can handle up to 3 PCI slots. If you have 4 or more, you have two bridges. North and South.

Mobo manufacturers split bridges up two ways:
1,2 and 3 North
4, 5, and 6 South; or

1,3,and 5 North
2,4, and 6 South

Either way, 1 and 4 end up on different bridges.

Video cards, sound cards and network cards are all resource hogs. When cards don't work and play well together, try shuffling them around so you don't get two resource hogs on one bridge. Try video in slot 1 and wifi in slot 4