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