My post you quoted had all kinds of typos, jheesh. Well, my guess, and it is a guess, is that they're basically the same design inside, but that Delta (I believe they're one of, if not the world's largest PSU maker) may use just a smidge better parts inside when it comes to materials choice, and if an expert reviewer had both disassembled, may find reasons to say the Delta was the slightly better product. As far as why are there two to choose from, I believe when Dell orders a batch of say 100,000 units, Delta will assemble as many as they can, and if any parts in their supply chain are short, HuntKey is contracted to pick up the slack. It's common for Dell to have multiple sources for the same parts, all that matters is demand can be met, which means there are Plan B partners, I assume like Huntkey. It is also possible that there's an arrangement that Huntkey is allowed to 'steal' the basic 850w design (in a world where Delta can't meet production demands), and perhaps can even produce them in bulk at a lower price. Pretend as well a scenario where Delta produces the bulk of the shipped power supplies while Huntkey produces the warranty units (in lower volume). When we go to the 80Plus website and get the Bronze certificates for both, the Delta scores a tad more efficient which may be due in part by including a better micro-electronic here or there, thus Delta is a name brand, Huntkey isn't. Where Huntkey may be a subtle knock-off design of the Delta, a less-costly substitute part, meaning Dell may pay $5 less for it. It's concerning of course that the name brand Delta has quality-control / noise issues, but otherwise, they're the same basic design inside to my knowledge, Delta scores just a teensy tad higher in efficiency which, given their reputation, makes sense. The fact it's noisy doesn't make sense, lol. I think the point is, when given a choice, go with the name brand big company with good reputation in hopes it can survive the warranty, but the substitute part is close enough not to worry too much which one you're using. If the Huntley used cost-cut materials, which is possible, they'd amount to dollars or cents, but not the type that make you lose faith in the whole basic design. I hope that covers it
https://www.plugloadsolutions.com/80PlusPowerSuppliesDetail.aspx?id=26&type=2