haggyy,
Unfortunately, we had a tomboy ..
Just now, I hope you will solve it well.
good luck.
update: If disabling "some unnecessary PCIE device" does not solve the problem,
"PCIE device enumeration buffer" may not be the only problem.
and It may also be a problem of TOLUD.
Just had a reply from ASRock Support:
Hello,
1. Please try to borrow more RAM to test with.
2. Try increasing virtual memory in Windows to at least 16GB.
3. The Molex power connectors on the motherboard must be used, even with powered risers. I know you tried this already.
4. Please try to test with Windows 10 version 1703.
Any change?
Kind regards,
ASRock Support
Trying this now
1 or 2 is suspicious.
Even if you disable "some unnecessary PCIE devices",
It may not be enough with only 4GB RAM to drive several GPUs.