Okay so I've been to my office a batch more tests on the Dynamo prototypes as well as the 300W AC-DC unit.
- I ran the single power unit stress tests with a second AC-DC unit (Prime 95/Furmark)
- The good news is it was vastly more stable than the first PSU and overcorrect protection didn't trigger despite the wall-read wattage bumping over 300W a couple of times. The other unit had OCP triggered each time I ran the test within the first 30 seconds.
- The noise I am talking about was there with both units, but it definitely isn't a conventional coil whine type of noise. If I had to describe it, it was almost as if there were a few small insects inside the casing and every now and then one will flutter up and bump the case grating then stop. I am sitting two-ish feet away from an open air unit right now and can hear it. Nowhere near as annoying as a coil whine and I don't think I'd hear it were it inside a case. I was the owner of two GTX 970 cards, so I consider myself something of an expert on how awful coil whine can be.
- Temperature on touch after 10 minutes of stress testing is lukewarm at best. I would say the temperature is lower than that at which I would bathe my two year old (Canada has severe penalties for child abuse, so I assure you it's very cool). Again were the unit dumping heat into the case, things might be different, but I was pulling 300W from the wall (260 from the brick) consistently during stress testing and I would definitely consider this the upper limit of what the brick is meant to do.
- The 7700K is expected to pull about 100W at full synthetic load which it does. The GTX 1080 at stock is expected to pull about 175W average at load with momentary spikes occurring frequently into the 250W range and sometimes beyond. As such this combo is likely pulling 350-400W fairly frequently under synthetic loads of this sort. Probably something as simple as going to a 7700 non-K or 7600K would eliminate the OCP from being triggered. Also the likelihood of actually pulling this sort of load in real system use is a virtual non-issue.