Over 4 Cards Won't Work, 5th causes endless reboot/noboot (MSI Z170 SLI PLUS)

[genstore]

I've been at it for about 8 hours and I need help.

Mobo: MSI Z170 SLI PLUS
Windows 10pro
All NVIDIA 10 series cards cards (2x1080, 1x1070ti, 1x1070, 1x1050ti)
PSU: 1200 Watts
Bios Version: E7A59IMS.180
Processor:  G4400 3.3 GHz (Non-Kaby Lake)
The problem is NOT with the GPU/risers/cables. Any 5th card causes this same issue (doesn't matter which card or riser I try).

I had 3 cards working just fine. BIOS is up to date. I introduced the 4th, changing virtual memory, PCIe link speed, and enabling 4g. No problems.

I try to introduce the 5th gpu, and I see the mobo splash sign appear then proceeds to a black screen. I have tried all possible combinations of using the 3 1x PCIe slots as well. Nada.


I just did a clean re-install of the OS/Reset the bios and started over. Still hicking-up at the same place.

I'm using the on-board graphics card plugged into HDMI.

[BitBustah]

I had thesame thing, but it was a PSU problem. The PSU couldn't handle the last card.

Is your PSU ok? If you have more PSUs, what is powering what?

[genstore]

I had thesame thing, but it was a GPU problem. The GPU couldn't handle the last card.

Is your GPU ok? If you have more GPUs, what is powering what?

PSU -->1080
PSU--> 1080
PSU Y SPlit

• 1070 ti
• 1070

(works fine with 4 cards, or any 1070ti, 1070, 1050ti combo)
PSU-->1050ti (right now, any comobo of cards dont work)

Adding the 1050ti card last is 75 more watts max, which seems pretty negligible compared to the overall power draw. With all cards in and peripheries, PSU load is @ 67%.