13 AMD GPUs on a motherboard: this is how

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I wrote in a previous post about running 11 GPUs of the 13 installed GPUs on AsRock H110 Pro BTC+ motherboard. I've been playing with the rig for the last couple of days and managed to get all 13 GPUs to work. Yay! I'm excited to share with you the experience. Do let us know if you've a better tweak. This is my DYI build.

Specs	Individual price(€)
CPU: Intel Celeron G3930	45.60
Memory: Corsair Vengeance DDR4 2166 MHz 4GB	35.00
GPUs: 9x Sapphire Radeon NITRO RX 480 8GB 3x Sapphire NITRO RX 470 8GB 1x Sapphire NITRO+ RX 580 4GB	~ 3250 (~250 each)
Storage: Kingdian 16 GB SSD	15
Motherboard: AsRock H110 Pro BTC+	200
Power Supply: 3x 850Watt Thermaltake Toughpower Grand RGB 80PLUS Gold	~ 375
DIY Case, PCIe risers, fans, etc.	100
Total	4020.60

A €4000 investment generates a little over $650 a month excluding energy cost. Though ETH is undervalued right now, it's still profitable. But I'm keeping the mined coins hoping the price will shoot.

Install Ubuntu 16.04 in graphical mode

First get the mining rig up and running with one GPU. Those new to Ubuntu or Linux, download and install Ubuntu 16.04. Consider downloading torrent (I seed too). Follow this excellent tutorial if needed.

AMD driver 17.30

Download and install AMD GPU Pro driver version 17.30. Installation instructions here.

Miner program

It's crucial. Do some research, for example, check which coin mining is most profitable at WhatToMine, NiceHash calc, and find a list of mining pools at CryptoCompare mining pool list. Of course, things change depending on coin prices and other circumstances.

Currently, I mine Ethereum and Siacoin at nanopool with Claymore's Dual miner. My aim was to run the miner with as few key strokes as possible. rtcwake for some reasons doesn't seem to work. Anyway, I added an alias in $HOME/.bashrc file. The alias command makes it possible to launch any command or group of commands (inclusive of any options, arguments and redirection) by entering a pre-set string (i.e., sequence of characters).
That is, it allows a user to create simple names or abbreviations (even consisting of just a single character) for commands regardless of how complex the original commands are and then use them in the same way that ordinary commands are used. I added an alias, eth-sia, to run the executable ethdcrminer64 with needed arguments such as (mytest) wallet address, pool. Suppose miner program is in $HOME/claymores-dual directory. Now edit the $HOME/.bashrc file and add an alias as follows:

alias eth-sia='$HOME/claymores-dual/ethdcrminer64 -epool eth-eu1.nanopool.org:9999 -ewal 0x9ef482576827b37c1838144e89D79FDD970cab89.h110-01 -epsw x -dcoin sia -dpool stratum+tcp://sia-eu1.nanopool.org:7777 -dwal ab53cd75f3002fbf8183ea8ba76bb45049c02df9531322435c38e975e7ca8af9b4e30f538b9c/h110-01/ -dpsw x'

See available options/arguments here. Instead of entering a long command, now just execute eth-sia and mining starts.

Remove display manager and enable autologin

X server (GUI) doesn't launch with 13 GPUs installed. So our aim is to turn off GUI and run miner program in text-only aka console mode. We'll enable autologin so that user credential isn't required when PC boots up.
Check if everything works till this step. If you can mine with one GPU, now it's time to get rid of Ubuntu display manager. Simplest way I think is to just uninstall it:

sudo apt-get remove lightdm

Enable autologin (only to avoid user login every time PC boots). I assume security isn't a concern because its only purpose is mining. In order to edit TTY1 config, run:

sudo systemctl edit getty@tty1

Now add the three lines:

[Service]
ExecStart=
ExecStart=-/sbin/agetty -a <username> --noclear %I $TERM

Replace <username> with the login username. Press Ctrl+O to save changes to TTY1 config file and Ctrl+X exit text editor. Reboot the system and see if it restarts in console mode.

Install all GPUs

By installing, I mean connecting the GPUs to motherboard with PCIe risers as well as to PSU with SATA power cables. Examine all the connections and, if everything looks good, power on the machine. When in terminal, run eth-sia, the alias we created earlier. Claymore's Dual miner recognizes all 13 cards and starts mining.

Here's screenshot of mining speed. ETH ~290 MH/s and SC ~8.5 GH/s.

Please upvote if you think it's useful (at least you don't need to pay for ethOS or SimpleMining OS which allow 13 GPU mining out of the box, of course, in console mode only. Also, there're privacy related things such as sign-up, IP, etc.). Do let me know what you think about the build and configuration.