I skimmed the article, but wanted to see a chart where they take the same system and just swap out the PSU to see how that affects power consumption at the wall. Like compare a no-name to bronze, silver, gold, platinum efficiencies to see how much you save.
As overall typical usage system power consumption goes down, I think it becomes less important to have a super efficient PSU, or at least it doesn't make sense spending huge amounts of money on it, because even if your PSU is inefficient, when you are talking about overall consumption of less than 100 watts most of the time, it would take years and years to pay off the difference in price between PSUs?
Yeah, for a typical desktop PC it's going to take a long time to pay off the difference if it's large. Heavy usage would obviously make the payoff faster, and might make it worthwhile. Even if you're running at 400W for 8 hours a day and 80W idle for the remainder (DC, not at the wall), the difference isn't huge.
Capstone 750W Gold 81.8%@79.4W, 90%@448W would be 5.12kWh/day
Corsair CX750M Bronze 78.7%@76.1W, 86.3%@376W would be 5.33kWh/day
Over the course of a year, that kind of high load would be 78kWh, which at $0.15/kWh is $11.70. Even at 2 hours at 400W and 22 hours at 80W per day, it's still 45kWh
Rosewill's updated the Capstone so it's not the exact same one in the review, but considering you can buy it for $55 after MIR, buying a $40 Bronze PSU like the EVGA 600B might not be worthwhile.
The reason why I'd spend more on a good Gold+ supply isn't so much the power savings, it's the other benefits like better cabling, lower fan noise, hybrid fan modes, etc.