I built 13 almost identical computers using Supernova 0750 G3 power supplies. So far two four of 0750 G3 power supplies have failed on two three different machines.
 
Both machines worked okay for a few days then crashed and would not POST, and the POST code indicator reads “C”. Which indicates a CPU voltage or a CPU power cable issue. Swapped out power supplies and they worked okay.
 
The voltage indicators on the X299 FTW motherboards were all illuminated and both power supplies tested okay using a power supply tester.
 
I let the defective power supply sit for 24 hours plugged it back in and it worked for several hours before the symptoms returned.
 
When I called to RMA the second power supply EVGA they said the first power supply I returned was not defective.
 
The two affected computers have not crashed since the power supplies were replaced.
 
EVGA X299 FTW K (13 computers)
Skylake i7-7820X (11 computers)
Skylake i9-7900X (2 Computers)
Samsung 960 EVO M.2 500GB (13 computers)
Ballistix Elite 16GB DDR4 2666 (11 computers)
Ballistix Elite 64 GB DDR4 2666 (2 computers)
EVGA GeForce GTX 1060 SSC (11 computers)
EVGA GeForce GTX 1080 (2 computers)
Corsair Hydro H115i (13 computers)
Corsair Graphite 760T (11 computers)
Fractal Design Define XL (2 computers)

Update the number of failed Supernova 0750 G3 PSUs PSU’s is now up to 4.
One of which was an RMA replacement.
 
RMA department confirmed the last two I returned both “crashed under load”. 
The two most recent failures resulted in damaged to two motherboard PCBs, two internal hard drives and one external hard drive.   The Samsung 960 EVO M.2 500GB drives were not damaged.
 
All cables are labeled for G-3
 
I used three sperate SATA power cables in each set up, one for the cooler, one for the internal drive and one for the optical drive.  

ATCUSN, our last email exchange was the same date as my initial post above, 5/4/2018 but I will send you another direct message 

EVGA finally agreed to replace the motherboards, they even paid for the return shipping.
Unfortunately, we’ll never know what happened to the CPU because FedEx lost it in shipping.