so there are some things wired directly into the cpu that bypass the motherboard. not exactly, but prettymuch.
I’ve seen a bad graphics card fry things.
Could be power supply, though usually that’s hard on the motherboard more than the CPU (if the cpu is the issue here)
what other pcie devices do you have?
most of the usb ports are not direct inteface.
if gigabyte says the motherboard is not bad, it suggests a peripheral is doing something bad on one of the internal busses.
All I have is a GTX 1070 FTW2… No other PCIe devices
check your monotor cables and see if there is a weird discoloration where the metal touches metal on the cables? to an extent thats normal but its possible that something is going wrong there… think about it in those terms.
even ESD discharge directly into the pcie bus could cause massive issues like you are seeing.
Im using display port cables and this happens only after I rebooted the system after running it a long time and not moving anything… I was able to reboot then all of a sudden I get no POST
Thats true.
However it happened to me once with a case that had one of its front usb ports damaged.
This also resulted in weird behaviour freezings,
boot loops, untill it didn´t wanted to boot at all anymore.
Of course what Gigabyte did with their testing is anybodies guess.
But they likely just put on a test bench to see if they got a splash screen.
They likely didn’t spend much more time on it.
But of course psu or gpu could also be the cause of the issue.
Or like i mentioned above a ground issue with the case.
Oh no they did even more testing the second time they got my board… They scoped components and did stress testing with various components for 2 solid weeks
so probably not the ram, board or cpu. leaves video card or psu. but psus have a habit of taking other stuff out too. and the 12v rail is pretty well insulated from everything else. and the cpu prettymuch only runs on 12v.
So … video card is most probably whats left? eyeball the video card for debris? bridged components?
Cards all good…
Good and bad are not what they would appear. Know anyone you can swap cards with?
I have a card I can use for testing or do you mean long term??? Cause this didnt happen for almost 2 years then 8 months the second time…
If in doubt and you can’t solve the curse.
Sell all parts to different buyers and start fresh.
Also, check that APC Surge Protector and PSU.
My money is on a funky interaction going on between those.
Btw, something that surprisingly no one seems to have suggested, but if you’re feeling very adventurous. Do a Murder test on your system.
That is run Prime95 and Furmark individually at first. Make sure all is well. Then run them together in ‘bursts’ (start/stop) while monitoring with HWInfo64 and listening to PSU and Surge pro while checking voltages.
Listen to the Surge Protector and PSU while doing this if you hear any clicks/buzzes/whine when the power load kicks over 9000.
Then kill the stress tests simultaneously and listen again. Repeat aggressive load/unload and see if something gets out of wack.
Disclaimer: This can go horribly wrong or work just fine.
If it works just fine, the power system is pretty solid.
I have a new supply and just haven’t built the replacement CPU and other stuff back up yet due to a forced move that has me depressed so I am dealing with that right now…
But Gigabyte even though they tested my MB to no end, they did replace it and tested the new one as well…
What I cant believe is no one on the earth has ever experienced this issue… 
I have experienced this issue before, but it was a power surge through a graphics card… and the graphics card survived… but the system only had one stick of ram survive (out of 4) not the motherboard (cpu did survive) the ssd and hdd did not survive and the psu had an audible whine to it after.
the graphics card did continue to work. somehow. How do I know the monitor did it? The monitor was not plugged into the power strip for some reason when the house was struck by lightning and the power plug that plugged into the wall melted. The LCD turned like a burnt brown in one spot and the PSU inside was charred.
Computer was off at the time. I wasn’t sure if the power strip was off (unlikely) or just soft-off (likely).
I mean where a CPU only dies and nothing else and it happens 2 times the exact same way… thats what kills me not knowing the root cause…
Time to study electrical engineering, you seem to have your bachelors thesis already.
Well It happened AGAIN… I changed all my hardware, even the front of my case and I moved even…
So with an entirely new system? Like not X99 any more?
What parts remained the same. Even down to power cables used or surge protectors.
No replaced the PSU, the face of my case, Gigabyte stressed tested the motherboard, determined there was nothing wrong with it, but for process of elimination they stress tested another board and sent me that… New ram as well… the ONLY thing not replaced is the GPU…
Well then that sounds suspect.
I am not getting on your case so dont take it that way, but that’s not changing all the hardware.
Really to test it would would need to find a way to cause it repeatably, strip the system down to bare essentials and test adding one more part back at a time till something goes wrong and that will tell you what part or combination of parts is the problem.