MSI X370 Gaming Plus
A8-9600
4 GB 2400
160 GB
1000 W PSU
1060 3GB MSI
1060 3GB MSI
1060 3GB Zotac
1060 3GB Inno3D
Win 10 Pro 1703 (lower builds cut hashrate)
Above 4g decoding enabled
UEFI boot enabled
7A33v54 BIOS
No issues with risers or gpus.
Wanted to make 5 gpu rig.

According to MB manual it can support 6 gpus with M.2 adapter, but I managed to run only 4.

1) When I put 3 gpus in slots 1, 2, 3 system starts with no problems.
When I add gpu to slot 5 or 6 MB won't start.
2) If I put 4 gpus in slots 2, 3, 5, 6 system starts with no problems.
When I add gpu to slot 1 MB won't start.
3) Slot 4 don't work at all as stated in MANUAL.
Please, refer to pages 28-29 of MSI X370 Gaming Plus MANUAL.

What am I doing wrong?