THIS is for those who have run into the problem of not finding a stable overclock and getting a bios code c.

I could not for the life of me fine a stable overclock with the 7980xe on the ftw k past 3.9 ghz. If you are having the same issue try changing the core voltage to 1.950 to 2.0 and apply. For me i changed the multiplier to 45 the core clock to 1.999 and left everything else auto stress tested for a few hours in the normal stuff like aida64 along with 4 other programs and total war attila maxed setting custom match with max army's. The custom attila match would often cause the crash even when I test aida64 for 5 hours. This post is just to help people hopefully find the same problem I had so they won't be forced to rma or breakdown the computers to examine every tiny thing for hours... cough.
I hope this helps someone.

1.9v?? Are you crazy?

My 7980XE (delid) runs 4.3Ghz at 1.10V drawing over 500 watts and EVGA CLC 280 barely handling heat with Prime 95 AVX torture (-3 offset on AVX, so runs at 4.0Ghz).  DO NOT RECOMMEND 1.9V. 

I have my 7820X overclocked to 4.4 and my voltage doesn't exceed 1.18, on my X299 FTW K.  Are you certain of the values you are posting?  At that voltage you state...you will kill that CPU sooner than later...

Let me clarify I wasn't referring to the core voltage that was my mistake. Cpu vin I think it's called as you can tell I'm a noob but I was referring to the voltage that sits at 1.8 ish for me to have any overclock I had to set it to 1.9 to 2.0 then bring it back down for whatever reason when I left it normal or auto it would crash my statem only in games my vcore or the 1.18 to 1.3 volts had to be set to a manual override or 1.295to offset of .3 i am still bring this down and testing. And i had to use evga eleet to set it anytime i set through bios it would cause the crash and bios code c would appear. Everyone kept telling me I had a bad cpu.
So current voltage settings are
Vcore. 1.298 target
Vcore offset 0.002
Cpu vin. 1.800 This is what I had to set to 1.9 to 2.0 then bring down not through bios tho.
Vmesh 1.2
Auto on everything else

Current clock is 4.5 ghz

So far it's stable even at load and in games temps peek at 51 c sit around 38to42 c I am watercooled ekwb kit loop.
I should have made sure of what my post was originally saying before posting it and sorry or the confusion.

I will test it.

I've tried that it will boot I can run stress test and pass but any game it with crash and give code c. Thanks tho.

I ran the tests for prime 95 30 mins and I ran the normal test for 30 mins each no crash.
Temps are 59c on 2 of the 18 cores the rest sit at 55c to 56c at 100% load at 4.5ghz.
Idle is 21c to 23c depending on core

I also ran furmark test at your settings and at 4k and all the other pre selected test no crash, I also ran haven no crash I ran evga of scanner tests no crash and played a 2 hour session of total war attila on max settings no crash. I also loaded up 50 windows on YouTube 4k videos and let them all play at once no crash... So seems stable

I have 2 hrs 1080 ti ftw water loop temps got to 44c otherwise they stay at 33c.
Power temp and memory temp all under 40c at load and idle at 38c and 35c
Plus 50mhz gpu clock offset
Plus 300mhz men clock offset
Max power at 117%

I have to use evga e leet tuning utility x to overclock it, if i use the bios or intel extreme tuner or any other way it will.cause the crash and code c. And I think that's not normal.

Cpu vin is sitting at 1.800 but runs at 1.826
Vcore is at 1.298 need to try and lower that but I wanted it stable 1st.
Vcore offset is at 0.020
Vmesh target voltage 1.200
Vmesh Offset null
And I don't know what RING is under the cpu core but core1-18 are at x45 bclk 100 ram 1066.7 not xmp 15,15,15,36,2t
quad 32 gigs