asrock z170. only working with 3 gpus

If there's any veterans I've read all the articles

1. latest bios
2. pci all to gen 1
3. used the amd driver mix 16.10 with 17.x (latest)
4. used pixle patch
5. tlud. set to 2.5g


once the 4th card is inserted we get no boot.

any thoughts ?