Hey
1. The booting and shutting down on first post of the system (even on bios updates) is normal, system is setting up. My comp also did it.
2. What bios setting are you using ? Try using only "optimized defaults" for now on.
3. Disable xmp if it is enabled for now.
Try again ;), remember, as stock as it is humanly possible
😉Max
Cpu : Intel 5930K@4.25ghz@1.2v / Cache @4.25ghz@1.20v
Cpu Cooler : Corsair H100i
Case : Corsair 780T
Memory : G.Skills 32GB DDR4-3200mhz CAS 15-15-15-35-1T@1.370v
Motherboard : Asus Rampage V Extreme (BIOS 3504)
M2 : Samsung 950 Pro NVME 512gb (Gaming)
M2 : SSD1 : OCZ RD400A 128gb (windows)
SSD1 : Crucial MX100 512gb (data)
Gfx : EVGA Titan X w/ 980 Hybrid Cooling AiO Liquid Cooler
PSU : Antec HCP-1000W
Monitor : Asus RoG Swift