Anyone still having only 4 GPU detected in Windows 10?

Hello Guys,
I having some problem here, my mining rig only able to run in max 4 gpus, no matter how i swap between pcie slots, still only 4 detected. I know this is a common issue, there is alots of people facing this & might found their solutions, but i tried most of them... non of it works for me.... Below is the specs & stuff i did

OS: Windows 10
CPU: Pentium G4560 (Was G4400, saw a post about skylake & kabylake limitation so i tried both)
RAM: Apacer 8GB 2133mhz Ram
SSD: Apacer Panther AS340 120GB
PSU: Segotep GP1350 1250Watts 80+ Gold
MOBO: Gigabyte GA-H110-D3A Mining board (Flashed Latest Bios, Mining Mode on)
GPU: 6x Gigabyte GTX1070 (Mix with Auros, G1 Gaming & Winforce edition)
Raiser: PCIe PCI-E x1 to x16 Riser Card USB3.0 Sata Power Connector

Stuff I did
- Flash Latest Bios Version F23a, Mining Mode on, GEN 2(was set automatically by bios once mining mode on but tried GEN 1 too)
- Onboard Graphic On (Bcoz i not sure if able to connect my screen to one of the 1070 with raiser connected)
- Nvidia Latest Driver Installed ver 384.76
- Changed virtual memory paging file size to 20000mb
- Installed MSI Afterburner (Using it to detect GPU always shows 4xGPU+HD610 onboard GPU and a blank clickable space at #6
- Tested every single raiser to make sure it's working fine (basically test every of them by plug in any of the PCIE slots with single GPU)
- Tested every single PCIE x1 slots (basically test every of them by plug in single GPU with raiser one by one, restart pc and run afterburner to check)

Please any advise or guidance is deeply appreciated, been struggled for days on this problem. TQVM