Better to invest directly in coins. The difficulty increases so fast.
A month ago when I started thinking of building a rig, calculation showed that I could get 5 Eth per month. But now only less than 3 (and it is pretty accurate). Essentially the Eth you can get will be probably almost halved every month until some point it is not profitable anymore.

a calculation:
＊ if you buy Eth with $3000, you can get 8.57 eth now.
＊ If you build a rig and assuming each month you get 60% Eth of the previous month: you get 3 the first month, 1.8 the second month,1.08 the third month, 0.648 the fourth month... guess how much you will get at the end of the world? 7.5 eths! And you have to pay the electricity bill.

You can use task scheduler to create a logon task on startup to run the batch file that starts claymore.
https://www.sevenforums.com/tutorials/67503-task-create-run-program-startup-log.html

In bios, advanced settings - Power Management Setup -Restore after AC Power Loss, set to power on, so that the rig will power on after power loss.

In windows, set the account to log on automatically, so each time you restart you will log in automatically (and with the startup task, run claymore automatically)
http://www.intowindows.com/how-to-automatically-login-in-windows-10/


I use afterburner to control the fan, but it has some problem controlling other settings. It is might be a problem with the driver. I use claymore to set core clock, memory clock and core voltage.


I found siacoin mining consumes more resources than decred. I have to turn dcri parameter in claymore down to not to interfere too much with eth mining. But with decred I can turn it up. Decred is more profitable than siacoin because you can have a higher hashrate when dual mining.

My risers have 6 pin inputs and 6 pin to sata adapters, so I use sata power cables mainly, for them. The molex is only used to connect the PSUs.

$ 6.25 per day?

Maybe try uninstall the current driver and install 17.5.2 with 5 GPUS, patch it, then shut down and plug in the 6th.
Not sure whether it work but if 6 470/480 work then bios setting should be fine, then might be a driver problem.
570/580 don't work well with earlier drivers. 

Two things more to add

1 PCI speed G1 should be OK. I use this setting and it works

2 You have RX 470 so after install the new driver you need to patch it if the cards have been moded.

Is this the one you have?
https://www.evga.com/products/product.aspx?pn=220-G2-0750-XR

In the picture it has a perif1 port and a molex cable with it.

I use MSI z170a gaming pro carbon in my 7 GPU rig and recently wrote about it:
https://bitcointalk.org/index.php?topic=1960777.0

A few things to check first
1 Your cpu: is it skylake? kabylake does not work I've heard
2 Mobo bios: must be v 1.7 or above
3 is your windows UEFI enabled? if not it won't work.

A few things to try:
1 uninstall your current driver, use AMD driver cleaning tool
http://support.amd.com/en-us/kb-articles/Pages/AMD-Clean-Uninstall-Utility.aspx

2 restart and in bios setting, disable 4g decoding in PCI settings

3 You should be able to boot into windows now. Download Radeon driver 17.5.2 (which I use and it works, newer ones may also work), install it. You should see in device manager cards recognized by some may have question marks on them.

4 restart and in mobo bios, enable 4g decoding

5 boot into windows and wait for it to recognize and set up all cards.

Should work now. Hope this helps.

I don't know TBH. But I saw a video on youtube about building an 8gpu rig using a z270 mobo.
https://youtu.be/NtxMhBWcxW0
The board is different though.

Yes, before installing the driver Above 4G Decoding must be disabled. Otherwise you can't boot into windows, it will be a black screen.

I use add2psu, which basically connects the ATX connector of the second psu with a molex of the first. The psu I use are
https://www.evga.com/products/product.aspx?pn=210-GQ-0750-V1
They do have a molex cable that can be plugged into a perif1 port.

My first mining rig!

Hardware:

• Motherboard: MSI z170a Gaming Pro Carbon
• CPU: Intel Pentium G4400
• Memory: Corsair Vengeance LPX Black 8G
• Hard drive: Toshiba 120GB A100 2.5" Internal SATA III SSD
• PSU: EVGA 750 GQ Modular Gold Rated 80+ Power Supply x2
• GPU: Asus dual RX 580 8G * 5, Sapphire pulse 8G *2

Luckily got 5 Asus dual cards from a local store and 2 Sapphire pulse cards from an online shop (stock went out in 30 minutes).

Install:
1 Update motherboard bios, see here https://forum.z.cash/t/msi-z170-7-gpu-bios-setting-step-by-step/14473
2 Change boot option in bios to UEFI
3 Install windows (UEFI boot)
4 connect GPUs (using PCIE risers), Settings>Advanced>PCI subsystem Setting, Above 4G Decoding set to Disabled
5 boot into windows, remove any installed driver using ATI driver cleaning tool
6 Install the latest driver (17.5.2), don't need to use the hybrid driver trick.
7 Restart and enable Above 4G Decoding
8 all cards should be recognized and work fine -- it took a while for windows to get all cards set.
9 mod bios
10 Start mining

Bios mod:
stock hash rate ~23 - 24 mh/s, after modding 29ish.
1 Asus dual RX 580: does not support uber mix performance timing (tried 3.1 and 2.3). Copy 1750 strap to 2000 strap.
2 Sapphire pulse: bios from http://1stminingrig.com/best-bios-rom-for-sapphire-pulse-rx-580-8gb-oc-hynix-memory-30-mhs/

Mining speed:
Claymore's dual miner ETH+DCR, with -dcri 36 - cclock 1200 -mclock 2025 -cvddc 900
ETH hashrate ~195 mh/s, DCR hashrate ~7000 mh/s
Could go higher but I don't want to hurt stability.

power consumption:
1200 W

Misc:
1 The memory clock of 4 Asus dual, and both Sapphire can go up to 2100, but one Asus dual can only go up to 2025. Setting memory clock for individual card in Claymore did not help. In the end I had to set one mclock for all.

2 Have to use afterburner to turn on and control the fans, otherwise only the fans of the GPU connected to the monitor spins.

3 Got stuck for a while with a bizarre problem that 4 GPUs work fine but 5 will cause windows reboot. Finally found that two GPUs connected to the same PSU always turn off before Windows reboots. Turned out that the problem was caused by a faulty PSU: it was OK with low load (can boot into system and run with 1 fully loaded GPU) but higher load (two fully loaded GPUs) turned it off. Replacing the PSU solved the problem.

4 z170a is a solid board, though I don't like the LED. It can be turned off in Bios ("Turn off LED control").