try :
1. Motherboard Asrock H81 PRO BTC R2,
2. Processor Celeron series G,
3. RAM DDR3 4 GB, SSD 128 Samsung (Recommended),
4. PSUs EVGA (adjust with how many and series of GPUs),
5. for GPUs NVIDIA (1070, 1070ti) AMD (series RX 480, 570,580).