Using Gigabyte Z68AP-D3 and can't get all of the 1x slots working.

It has the following ports
x16 x1 x1 x16 x1

both x16 slots work fine with with risers with no shorting required.
the far right x1 slot works with no shorting required.

the middle 2 1x slots I can not get to work at all, even if they are the only slots in use it will never detect the cards, even with shorting, anyone have any ideas?

Ideally I would like a 4x GPU rig using this mobo, so I just need one of the slots to work