so i was reading online that pcie x1 slots are routed through chipsets generally.  the b250 chipset on this board has a max of 12 pcie lanes so that seems pretty spot on with the amount of gpus this mobo can run.

 I can run 9 no problem so I need to figure out what is occupying the other pcie lanes.  Is there an easy way to find out whats on those pcie lanes or is it only possible by disabling certain things in the bios and seeing if that frees up a pcie lane? 

I have so far tried disabling all sata ports, lan controller, audio controller.  I guess i can try disabling the usb ports but then i wouldnt be able to control the bios afterwards.