Thanks for your info guys, one thing i want to buy a 1070, what is the best one right now.
For overclocking and stability. also its hot here in the summer what you recommend me to do watercooling?
or is it way to expensive, also i found a motherboard i want to buy 8 GPU's so i need m2 risers and a motherboard that supports it.

Think this one will do fine Asus PRIME Z270-P
also i need Power do i need a 750 x 2 or just one 1200 watt power supply.

EVGA GeForce GTX 1070 FTW GAMING 8GB - 500 euro
MSI GeForce GTX 1070 GAMING Z 8G - 516 euro
MSI GeForce GTX 1070 GAMING X 8G - 448 euro
Gainward GeForce GTX 1070 Phoenix 8GB - 443 euro
EVGA GeForce GTX 1070 SC GAMING ACX 3.0 - 464 euro