1089
Steam Deck OLED announced
(www.steamdeck.com)
This is a most excellent place for technology news and articles.
I only have a Deck but 9 watts has been the magic number for me. Good battery life and very little fan noise in most games. I even run RDR2 at that with Cryobyte's "prettiest" settings, and it stays darn close to 30 FPS. I may have bumped down far shadows and water a notch but honestly it still looks great.
It's definitely a matter of taste, but you still get a lot of performance per watt on the Deck between 9 and 12, so I typically prefer to crank it up a notch and aim for 35-40fps instead.
Which option is preferable probably depends on how sensitive you are to low fps vs fan noise, so there's no right answer.