GPU not detected on pci-e 16x slot with usb pci-e1x riser

[Aureliusy]

Motherboard  (Asrock B150A-X1) has 3x PCI 1x and 2 PCI1 6x slots. Run on Windows 10 with 1060 GTX
If i connect a USB PCI 1x  Riser into the PCI16x slot it is not recognized
Tried setting all slots to GEN1 and GEN2.
Tried connecting it as first and only  card (monitor stays in sleep mode)
 
What works
One GPU is directly connected to PCI16X slot =  recognized
All 3 PCI 1x slots work ok with PCI1x 16x usb risers.

The GPU , cables and riser are ok.  I tried in in the working slots ..
Currently mining with 4 cards, but 5 would be nicer.

[666mrga999]

Same problem but with different MOBO (MSI Pro Carbon).
Would like to see a solution.

bump