I agree entirely that never cheap out on a good PSW and even if after troubleshooting it isn't the problem I would still recommend it with the age of the previous one. That being said, I don't recall if you noted whether or not this is a new build (believe it is) but as Fox and Gospel mentioned does strike me as odd if your system really is drawing that much.
I think if it were me the first things I would do is
1. Ensure your temps are never spiking over recommended ranges and
2. (my gut instinct w/o knowing anything else) remove all but 1 of your memory dimms and test then remove that one and put another in test, so on so forth until all have been checked. Also check same stick in multiple dimm slots, to verify no error there as well.
From what you've said the only thing that is really giving me goosebumps is that you mention having graphical artifacts. That tends to be a video card memory issue. You don't happen to have a secondary card or onboard video that you can check do you?
Finally, check this site out
https://outervision.com/power-supply-calculator as it should give you an idea if your system is drawing as much as you believe it is. It won't rule out age of your current PSU but there are tests you can run under load to see if your voltage is dipping too much.