Maybe not identical, I couldn't say unless I had them side by side and opened up. I did ask Seasonic, I already had one that was 7 years old and they nicely sent me a 12-pin for my GPU even though it was not from their current line up. He even said the Phanteks was good as the shipment of Seasonic to EU region was delayed.
But look at it like this, I was with Smarty for my mobile phone £20pm no contract, can cancel anytime. Went direct with 3, using an offer got £18pm but generally they were £25pm at the time. The masts I use work exactly the same. Smarty use 3 but can charge less. Just because you see branding/marketing etc doesn't mean your getting anything more than what the parent company or infrastructure make. Look how many broadband providers are cheaper than BT (they travel over same equipment as BT)?
If your telling me Phanteks use B grade parts when the guy on the Seasonic CS desk tells me the OEM rog and phanteks are made by themselves and are same components... thats all I needed to purchase. I can confirm the cables are seasonic, identical.
Like I said manufacturers can make all different levels of parts. I'm not saying they use b grade parts. And have all different kinds of testing, qc, packaging, brand and advertising costs attached.
The phone example is actually quite good - not sure about smarty but when Tesco used o2s masts, they were indeed using exactly the same masts however would be second in line for data/connectivity. However... They had different customer service! See what I mean? There's a lot of different variables within company setups, we couldn't even begin to understand them even if we knew.
Sony/Toshiba/others use LG panels in their tvs. As well as boards. Are they the same quality? No.
Samsung use Sonys OWN camera lenses - are Sony phonebcameras better? No. Wtf?
There's a factory in China that produces FAKE products AND real versions of the SAME product. Are they any different to the real thing? You might not even know!
Another example is like 90% of aios all have asetek pumps. Yet theyre often different in quality. You've got your £50 bargain basement chinese ones and your £150 nxzt ones. Both chinese at the end of day, probs made in the same factory. One brand has 3 star reviews one has 4.5.
Personally though if an actual rep told me they were exactly the same, and *specifically* said they use the exact same parts and had the exact same level of quality (I'm not sure they did that) then I'd buy the cheapest. I don't want to pay for packing or branding. You'd be damn right to buy the cheapest.
Something as simple as cables I would expect all the top (and maybe even cheap manufacturers) get them from the same company.
That's not something I'd be worried about them skimping out on though, more likely the capacitors and stuff.