ATX power supplies are not rated for sustained 24/7 at full load. There is a reason servers use much higher quality PSUs and not some ATX crap you would put in a home computer.
Think vehicle tires.
You need a 10 ply all terrain tire and you have been running off of a donut spare this whole time. Does it work? Yes. Will it end badly if you use it for too long? Yes.
Go get a real server grade PSU!
The EVGA Gold and Platinum rated have performed fine in all sorts of "interesting" applications. I would be surprised overloading it is the problem here. I use one in everything I build from gpu rigs to gaming machines.
I would be *surprised* if the PSU was the problem as long as it wasn't overloaded. (1400w on a 1600w psu seems like too much , but I would think the psu itself would fail first.).