I’ve just signed up to let people know I’ve been successful in getting 6 GPUs to work with the Asus H170 Pro Gaming motherboard, here’s how I got it to work (after much reading and trying different things):
- Update to the latest BIOS
- Enable new setting in BIOS “Above 4G Encoding”
- Installing Windows via UEFI, not the standard MBR version (easily done with a little application called Rufus to create a UEFI bootable USB)