Thanks Citronick. Maybe I got a bad mb. Tried to insert molex as well. Just did not work. I am using a 570 on the fourth slot. It hashes but the result is not stable. from 8M to 26M/s.

Updated:
From your previous post I learned that I may use smOS. Turned out it works great! Now seemed everything works! Thank you!

Can you power the molex too - looking at the mobo design, the sata and molex power ins - it appears that would the risers would have needed.

I am using low power GPUs like P106s for this mobo and later testing the RX470s - I am not confident yet that this mobo can take heavy duty GPUs like the 1080tis until I test them.

Note: I am not at warehouse today - I got my office people to take pictures this morning.

In BIOS, set automatic on after power failure/off.

Work in progress, 2 x boards, 6 x 2 = 12 x ZOTAC P106s, 2400w Delta and 1 x EVGA-G3-1000w powering 3x2=6 SATA and 3x2=6 Molex.

Without the SATA and Molex powered, only 1st GPU works.

My local supplier told me that P106 has been restricted to bulk/farm orders and not for retail sales anymore  

Tried. It didn't work out.

Actually I see no difference, whether to plug GPU into MB slot or riser. Whenever I plug GPU into two last PCIs, Windows sucks – that's the problem.

ASRock Fatal1ty AB350 Gaming K4
Ryzen 5 1600
2 x 4GB DDR4
3 x MSI 1060 3GB
2 x GIGABYTE 1060 3GB
1 x Inno3D 1060 3GB
Windows 7 Ultimate

6 video cards DO NOT work on ASRock Fatal1ty AB350 Gaming K4, at least on Windows 7 and 10.

I tried a lot, but managed to make 4 GPU rig on this board, which works like a charm with 385.69 NVIDIA driver.
AMD 16.50.2601_Allin1 drivers (USB, etc.) aren't installed.
Almost everything disabled in BIOS.
BIOS updated to 3.20.

If I put GPU into any of last PCI slots, Windows won't start. It doesn't matter, whether one GPU is installed or four. Just put additional GPU into one of last PCIs and Windows won't boot.

In safe mode Windows shows 6 GPUs, BTW.

Do you recall what you changed?  Did you just swap cards in random slots until it worked? Were you installing drivers? And did you get 5 or 6 working?

Can potentially save me a lot of time later.

When using AMD Cleanup or DDU, should I:
- remove all but 1 GPU
- Disable 4G Encoding
- boot to safe mode. 
- run cleanup
- Then reinstall as normal

Or can I just do it all from a normal windows boot without rebooting.  I imagine I'll get a black screen if I run DDU and reboot with 4G Encoding enabled. 

I know, I know, I should try it.  12 hours from now I will. 

Hi, what hashrate is on Ryzen R5 1600X?

Anyone care to share RX 570 hashrates with the new Claymore + blockchain driver for dual-mining ETH+LBC please?

Well I had a problem once in which no card except the amp extreme 1070 would work in my first pci-e slot .
I tried clearing bios , reinstalling windows etc everything nothing seemed to work.
So I didn't put any card in the 1st pci-e slot
and put the rest of cards in other slots and let it run for a day or day and a half , that amp extreme 1070 was now in slot 4 or 5
anyways afterwards I had some internet problems during which I couldn't mine so I thought why not try to fix this issue
I completely turned off the rig , attached a 1060 card in the first slot , Others cards still in their slots and tried to turn on the pc.
Too my complete surprise the card worked and every thing is still working 1 month later now.

The rig boots fine, whatever the number of GPUs.
It's just that one of the GPUs is not recognized by the driver. I can still see it in lspci, though.

CPU is Intel(R) Celeron(R) CPU G1840 @ 2.80GHz

Update: I replaced all GPUs with 750Tis. 6 of them. And they all worked fine.
Another pointer towards the PSU: a Corsair CS750

I wonder if I will be able to achieve 500+ H/s @ cryptonight(xmr) on a ryzen 1700?

After spending far too much of my life on this I found this thread.  So I decided to post my story.

I have an asrock ab350 gaming k4. I have a mixed rig. I had 4 1060s and 2 580s to put me under my 1000w psu.

I originally bought two of these rigs.  My first had no problem with 5 gpu and is still running 5.

The second rig I fought with.  And fought.  And fought.  It was 3 months ago so I don't recall the details but I believe  I was able to get 6 cards running by installing drivers one by one and mucking with slots. After it was running it was totally stable and never did the black screen booting windows ->recovery. .  

Last week a fan died in the second rig and I swapped a 1060 with another 1060.  Nothing else changed and now the machine will not get to windows with more than 4 cards. I had forgotten about the initial pain of setup and now I'm pretty pissed.  

However, I did have  a m2 to pcie card laying around. So props to the previous post about trying that. I originally stuck it in m2_2 -and windows didn't see the card.  So I tried m2_1 and moved one gpu out of pcie 4. Now I have 5 cards running.

Later, I might try to get the 6th working.  I'm thinking if I boot to safe mode and install the drivers for 6th I might be able to get it going.  

Quick ROI is not the point of this miner, and if you want to buy 10 to just mine for profitability your better off getting a large ASIC. Its not possible for a single stick USB miner to be anywhere near as profitable as a large ASIC or GPUs because of economies of scale.

For example this miner half of the cost goes to ASIC, and the other half goes to assembly/component costs. For large miners its 90% ASIC cost and 10% Assembly/components because they can stick hundreds of ASICs into one miner.