I have not done any BIOS flashing on this card, I would think it seems a little far fetched without any official mentions that it could improve power efficiency without tinkering with general performance.
There is nothing special about my card or its settings, it should all be default, if I had to guess what matters it is the resolution + refresh rate and however many screens you have, but im a little surprised that you are seeing even worse results when you have 4x 1920x1080 @ 165hz which should be less resource intensive than my 3x 2560x1440 @ 144hz perhaps its an indication that more displays use more power in general, have you tried testing with 3 instead of 4?
I have no idea how to replicate the artifacts, it is seemingly random but I suspect it happens when the card wants to do something e.g. decoding video streams or w/e, I really have no idea lol.
Edit: P State 16 is actually not a thing, its labeled as undefined and 15 is the highest you can go that will yield the lowest power usage, here is a recording of what I am talking about: Watch artifacts | Streamable