I mean... I run an overclocked reference Vega 56 in a Node 202 off a 450W PSU and it's performing within margin of error of a GTX 1080 without even touching the limits of my power supply. The "Vega is hot and hungry" meme comes from people pushing balls-to-the-walls overclocks on the Vega 64 Liquid BIOS, which can and will pull 600W alone.
As for the topic of the thread, I like the rumors but I will always be wary with AMD rumors. With the initial Ryzen parts they managed to smash expectations, but there have been many times before where the rumors were too good to be true and everyone was left disappointed.
MMmmm....no, it came from vega drawing, at stock, more power then geforce cards.
just because your vega 56 OC runs on a 450 watt PSU doesnt mean it isnt drawing more power then the 1080, if fact it is a guarantee it is pulling more unless you got a golden die. Lets see your system power consumption under full load OCed with a kill-a-watt meter, then compare to the same system with a 1080. I'll bet good money the 1080 system will pull noticeably less power then an OCed vega 56.
Vega was slower and more power hungry, thus hotter, then geforce cards were, came over a year after the 1080 came out, and were more expensive. A vega 56 still costs 1080 money. The RX 580 and 480 offered 0 upgrade path for many, being as fast as a 290x, which had been out for several years by that point and had been available for ~$250 at one point after the first mining craze. AMD dropped the ball, hard, and has yet to pick it back up in the GPU space.