Ok re-watched the whole thing listening as well as watching, and saw he mentioned the Gigabyte watercooled card he has a vid on.
Here mentioned:
And he's remembered it wrong because here's the test:
So it's a difference of ~20W on average (133W vs 153W), at 1475 MHz vs 1470 MHz. With the gigabyte crashing after a little while.
Managing 5 MHz extra, plus stability, with 20W less power draw under heavy overclock is VERY MUCH within the realm of a golden sample card with a custom PCB.
This is clearly NOT a revision card. AMD is just experiencing a huge variance in die quality from GloFo. There seems to be something wrong with their first revision of 14LPP, and there's reports they've revised it and are unofficially calling the new one '14LPP+' (which coincides with this speculation of an RX 485).