Hi,
You may consider buying this set
x2 :
- MOBO : H81 Pro BTC (handles 6 GPUs)
- CPU : Intel G1840
- RAM : any 8g stick
- cheapest SSD you can find with 32g
- 1 lepa 1600W that can handle 4 gpu and another 700-800W for the 2 left
Buy 2 more R9 and you should get 2 6xGPU rigs for yourself, great start indeed
tis is pretty solid advice. however the H81 is tough to find. the H97 anniversary is equally good and available everywhere for ~$100.
the ssd is good, but you could use an HDD as well if you have one around or can find a small one for cheaper than the ssd
1600W power supplies are often very expensive. you might get a better price with 2x 1200W OR IF MINING
ETHEREUM YOU ONLY NEED ~120w/280x and a single 1000W PSU could suffice because it has lower power draw from the cards