Anybody can assemble a mining rig with a little patience and a base level knowledge in computers.
The mission: Attain highest possible profits while using the least possible power consumption.
The Build is going to be as bare-bones as possible in regard to the processor, RAM, storage, and even the motherboard.
****** THE BUILD*****
CASE
Build something with screws and 2x2's. Look it up.
MOTHERBOARD
Basically any H or B series motherboard should do. It should ideally support 4 or more graphics cards.
GRAPHICS CARDS
Based on my findings, the choice GPU for mining seems to be the RX 470. At stock settings the 470 consumers 120 watts when the 570 consumers 33% out of the box at 180 watts. Although kids are getting really good at underclocking in MSI afterburner to lower power consumption and in turn increase on overall profitability. It's not unheard of to get these cards around the 80-100 watt mark without hindering on the hashrate too much.
PCIe CONNECTORS
Because your motherboard isn't the red carpet you can't directly plug in all of your GPU's directly into your mobo.
PROCESSOR
You don't use your processor much at all. Any aftermarket Pentium processor should work. Just make sure your motherboard is compatible with it. Bottom line just get a very low power usage Pentium processor. Might be a good idea to pick up an aftermarket cooler just to be safe since it's going to be on 24/7 or close to it.
SSD
Don't get a hard drive. They use more power. You can get your hands on a 60 GB solid state for well under 40$. You can get a TB of hard drive for that cost but you won't use the storage and it uses more power to run.
RAM
I would recommend buying a single 4GB DDR3 1600MHz stick of RAM. Having more RAM won't help you.
POWER SUPPLY
You want a name brand power source. A gold certified/platinum certified unit is choice. I cant exactly tell you which one to buy. You need to do research on how powerful of a power supply you need.
LEARN WHAT OPERATING SYSTEM WORKS BEST FOR YOU
DON'T USE WIRELESS CONNECTION. ETHERNET IS THE BEST WAY IN ENSURE YOU GETTING THE MOST STABLE CONNECTION.
IT'S UP TO YOU WHAT MINING SOFTWARES YOU USE. THERES BTCMINER AND CGMINER.
DOWNLOAD MSI AFTERBURNER AND LEARN ABOUT UNDERCLOCKING.