Okey I got it working on my MSI Z170A Gaming M5 motherboard. Got all 8 GPUs detected and working on Windows 10 1709. Did bios update and I got "Above 4g Decoding" option. Set it to enabled, and set PCIE speed to gen2.
Popped 1to4 risers to each PCIEx16 slot, plugged 4 GPUS in each. You don't even need UEFI , my ssd had generic MBR partition and it worked fine.
So, still confused if it will work on other chipset. Currently Z170 motherboard is costlier than current gen. Is there anyone who can confirm this working on entry level B250M motherboards?