You HAVE to give the mobo that 4-pin, or it won't work with all PCI-E slots filled. Plus, having the extra power is NOT going to fry the risers. Power doesn't work like that.
OK then i will TAKE A PHOTO of ALL my rigs that have x6 GPU's (ALL 6 PCI-E slots filled) mainly 480's (i have other setups also) WITHOUT any molex 4-pin connected that work perfectly for months
and post it here...(after i get home that is)
PS. I am using ethOS but Windows 10 works as good without problems