Corsair HX 1200 and EVGA RTX 3080 FTW Ultra 12G. Just crashed my system and now I have no video output. The card is dead. This will be my third RMA. I was playing Conan Exiles. I am posting because I noticed the HX 1200 was listed as working. I popped in my old RTX 2060 and everything works perfectly.  

Cinchona
Corsair HX 1200 and EVGA RTX 3080 FTW Ultra 12G. Just crashed my system and now I have no video output. The card is dead. This will be my third RMA. I was playing Conan Exiles. I am posting because I noticed the HX 1200 was listed as working. I popped in my old RTX 2060 and everything works perfectly.  

It has nothing to do with the power supply.
That's why this whole thread is pointless.

The EVGA SuperNova G2 1600 is not working with either the 3800 and the 3900, but is showing on the list.  

johnpando
The EVGA SuperNova G2 1600 is not working with either the 3800 and the 3900, but is showing on the list.  

Again, it has nothing to do with some magical power supply list.
That's why this whole thread is pointless.
"The list" means nothing.

So wait....if I had a 2060 TI installed in the system with all the same components and it worked fine for 2 years with the 1600 SN G2 it forms a baseline. I replaced the 2060 TI with a 3080 TI and only than started having the problems with the video card shutting off under heavy load, while the rest of the system continues to run.  Reinstalled the 2060 TI and runs just fine under load.  Than just to prove the point I installed a new 3090 with the same behavior occurring.  Doesn't that seem suspect to you?

Contact EVGA and have them replace your defective power supply.
There is no model of power supply that will make the card work or not work. Cards and power supplies fail due to defects or age. There is no magical list.