Since your power supply can handle up to 850W that will not be enough for your cards. The recommended wattage for your GPUs is about 900 W.
Not to mention that you also need to plug in other hardware devices like a CPU, HDD/SSD that also require power. You can setup your configuration here:
http://www.coolermaster.com/power-supply-calculator/ But, when you optimize the GTX 1060 it only draw 80w per card, 6 x 80 = 480w for the GPU on the 12V rail. The corsair 850w has on the 12V rail 850w this is more than enough.