For those of you running the preview build of SteamOS, you may want to hold off on the latest update – “The OLED Update” – for now. They’ve changed the color profile, and the intensity slider to boost the colors is now far less sensitive than before. Setting it all the way to the max has less effect than setting it to “SRGB” in previous updates. Additionally, VibrantDeck is broken, so you can’t even use that as a workaround. The only option is to switch back to Stable or Beta and settle for VibrantDeck.

Definitely recommend that you hold off on this update until Valve can push another one restoring the prior functionality.

EDIT: Turns out this Preview update also ruins performance and messes up the fan curve. Just a disaster all around, this one.