https://youtu.be/f6snWfd1v7M
This is what I mean by lasting. That unit has 3 12v rails for a combined wattage of 450w, or about 37A. That's severely inefficient for a psu. It's built on a 2010 or before platform, probably based on old AT standards, with its 24A minor rails. Having only a single 75w 12v pcie 6pin out of a possible 450w 12v is bad. You can always tell what a psu can handle by its connectors, a 600w unit should have at least a 6pin and 6+2 pin minimum. While it might claim 450w on that rail, chances are very good that any loads over 1/2 that will jeopardize the integrity of its minimal protection circuitry to the point where it follows the psu's in the above video. I for one will absolutely not recommend it be used or even attempted on an expensive, high power card like the 980.
I agree with madmatts choices. 3 solid psus well able to reliably power that gpu.