Help please Windows can't recognize 6th card NVIDIA

Hello guys, I have one (first rig)1080x6 RIG and now I made (second rig)1060x6.

On my first rig I managed somehow to make all cards working, of course it didn't happen right away, I spend hours but finally I did it.

On my second rig I repeated all I did on my first rig but still cant make 6th card working. It doesn't appear in Device Manager at all. Power is enough, the problem is in Windows or NVIDIA drivers I don't know, I use the same driver as in my first rig. 4G decoding turned on

Please help to make this working, I searched over the internet and I find info only about AMD, I hope if we find solution many people will be glad we did.

MB: Asus H270-Plus
RAM: 8GB
PSU: Corsair AX1200i

I'm still waiting on my 5th and 6th card to arrive, but to get my 3rd and 4th card working I found 2 devices not listed under display adapters (can't remember now what it was under, but it didn't look like the sort of thing a graphics card should show up as) and installed drivers for them. Have you ruled out the card or the riser being dead?