My FX 8350 running on an Asus Sabertooth FX990 rev1 runs fine and windows 8 pops up. BTW wow that's the longest run on sentence I've ever seen. I know you are upset and I would be also.
May I ask if you installed all of the chipset drivers for your mb? Did you check device manager in windows to see if you are missing any device drivers? Truthfully that's the first time I've ever heard of this problem. What CPU cooler are you using? Have you run just 1 6970 to see if this problem occurs?
Asus Sabertooth X79 3930k @ 4.6 Ghz Swiftech ApogeeHD | Gskill 16G DDR3-2133 (4x4 quad channel) | 2 Sapphire Tri-X OC R9 290s in CF with EK wtrblks | Intel 530-180g (OS); Intel 520-120g ; WD Black 500g | Silencer MK III 1200W psu | Custom watercooled XSPC RX360 + MO RA3-420 Pro + XSPC Twin D5 bay res | BenQ BL3200PT 32" 2560x1440 | Win 8.1-64