I think I found it...
https://bitcointalk.org/index.php?topic=1891461.240
Quote
I want to lay down everything that I have experienced and learned a day before to set up my 6x RX 580 Sapphire Pulse 8GB in Windows 10 Pro with Asus Z270A Prime MOB.
1) Install Windows 10 Pro w/ only integrated GPU & no Dedicated VGAs connected.
2) Check for updates of OS.
3) Install drivers that are required for you MOB to work efficiently, by going to your MOB support page. [UPDATE to latest BIOS]
4) Now, go to 1stminingrig.com and search for their windows tweaks. Apply all of them.
5) Download latest 17.5.2 Relive drivers and extract them in C: Folder, don't install yet. Just Extract them.
6) Shut down your system and connect all of 6x VGAs.
7) Go to BIOS and make sure you make the following changes:
- x16 Link Speed: Gen2
- PCIe Link Speed: Gen2
- Disable HD Audio Driver (We don't need audio and in some cases, audio driver shares a lane and it may cause problem with one VGA)
- 4G Decoding: Disabled
- Memory Remap: Enabled
Cool Start your system, go to device manager and it should show six VGAs with Microsoft Basic Driver.
9) Just go to the primary driver that is connected to the primary x16 lane and manually install the driver by locating it to driver folder in step 5.
10) It'll install Driver for all 6x Cards.
11) Go to BIOS and Enable 4G Decoding now so that there are enough available resources for all the cards to work together.
12) Done! It should boot up with 6 cards detecting and up and running.
1) Install Windows 10 Pro w/ only integrated GPU & no Dedicated VGAs connected.
2) Check for updates of OS.
3) Install drivers that are required for you MOB to work efficiently, by going to your MOB support page. [UPDATE to latest BIOS]
4) Now, go to 1stminingrig.com and search for their windows tweaks. Apply all of them.
5) Download latest 17.5.2 Relive drivers and extract them in C: Folder, don't install yet. Just Extract them.
6) Shut down your system and connect all of 6x VGAs.
7) Go to BIOS and make sure you make the following changes:
- x16 Link Speed: Gen2
- PCIe Link Speed: Gen2
- Disable HD Audio Driver (We don't need audio and in some cases, audio driver shares a lane and it may cause problem with one VGA)
- 4G Decoding: Disabled
- Memory Remap: Enabled
Cool Start your system, go to device manager and it should show six VGAs with Microsoft Basic Driver.
9) Just go to the primary driver that is connected to the primary x16 lane and manually install the driver by locating it to driver folder in step 5.
10) It'll install Driver for all 6x Cards.
11) Go to BIOS and Enable 4G Decoding now so that there are enough available resources for all the cards to work together.
12) Done! It should boot up with 6 cards detecting and up and running.