Relying on some random spreadsheets from sites like TPU is usually a bad idea. A beefy rx 580 card like the Nitro+ can draw even more than 185W when dual mining, here's the consumption of the similar card (nitro+ le) measured in gaming:
http://www.tomshardware.com/reviews/amd-radeon-rx-580-review,5020-6.htmlAnd dual mining often puts at least as much load on the cards, sometimes even more.
The PSU choice depends on the conditions the cards will be used in. And no one runs Polaris cards at stock voltage for mining, it's just stupid. I've got a couple of Nitro+ 8gb cards, and they were drawing ~ 160-170W
from the wall in dual mining at ~ 0.9V.
So yeah, if the OP is not an idiot, he'll do just fine with that HX1200. And more than fine if he's not planning to dual mine.
We are using technical data here just for reference.But yes, in fact, modded Polaris cards running Under 100 Watt voltage but what we are discus here is to find a solution. Let's see, what I'm saying is the
save way to keep our part Of mining in the good condition and for an along term mining process. But if OP wants to use HX1200 it's fine, but I suggest OP using PSU with more extra Power. Such as using 2x700 or whatever for more securing all of your devices.