please help me, i'm new at this kind of mining thing and i got this problem. my rig crash when i start my claymore miner after i add 1 more gpu at my rig.... here my rig specification

- Motherboard = ASROCK H81 Pro BTC r2.0
- GPU = 2 x Powercolor RX 580 4 GB + 1 x Sapphire Nitro+ RX 580 8 GB OC edition
(my rig run normally when i unplug the Sapphire Nitro+ card)
- 4 MB RAM
- PSU = Corsair HX1000
- OS = Windows 7 Ultimate 64-bit
- Miner = Claymore v9.8 (only ethereum)

please help, i can't find the answer at the google... thx