Hello dear miners!
I'm wondering if my Thermaltake SmartSE 730W Power Supply can power 3x AMD Radeon RX580 + 1x Nvidia GeForce GTX 1070
Is it enough or do I need more power?

Check corsair 1000rmx for that. One 1000w corsair powers 5x rx580. Also do not forget to careful connection with PCIe power cables and sata. And no more than 2 GPUs on 1 sata power cable.