After I looked at the pictures, I have some questions.
1. How do you power the risers? PCI-e SATA?
2. How do you decide which PCI-E slots to use and which don't?
3. Why you don't use the PCI-E x16 slot?
Maybe the key to resolving the problem is in these answers.
1. MOLEX/SATA.
2. I read on different forums/topics that the first must be filled black slots, than white, but I tried various configurations.
3. I use at now, I filled all black slots and two white.
Like i said i tried many configurations/manipulations with BIOS/pci-e slots/other PSUs/risers, but it didn't work.
I have one more rig with the same MB on 10x Gigabyte RX480 8Gb and it works perfectly.
I think it's incompatibility in MB + VC, I read some topic, guy have the same problem with this mb and the same cards XFX RX580 GTS. I just configure script and over with that.
Even if you are happy with the script, I recommend getting rid of the SATA cables for safety. They are not designed to carry up to 75 Wats as the riser needs. I know these GPUs use less power even under maximum load, but safety is my first priority. If you don't want to change PSU, a better option than SATA is to get good quality PCIe splitter cables.
If there is an incompatibility in MB with GPU, swap the MB. Move the XFX to another MB and get the GPUs from there on this.
