SteamOS beta patch 3.2 lets you chose the screen refresh rate (and more inside)

[Kupfer]

Just stumbled across the new Phawx video and haven't read anything about it yet.

• Added an OS-controlled fan curve to improve the experience in low usage scenarios, and adjusting how the fan responds to different scenarios and temperatures.
• Fixed an issue where OS fan control would not automatically resume after waking up the device from sleep.
• Added experimental support for changing the in-game screen refresh rate. The refresh rate will automatically be adjusted to the desired option when going in and out of game.
  • There is a new slider in the Quick Access Menu > Performance tab that allows you to choose a screen refresh rate between 40-60Hz
  • The framerate limit slider values will update accordingly, and will include 1:1, 1:2, 1:4, or uncapped framerate options.
• Fixed an issue with typing the € key using the Steam keyboard
• Added experimental support for bringing up the Steam keyboard automatically in some cases in Desktop mode

-source

This is a great update! Playing at 40hz / 40fps offers a good compromise between playability and battery life and the annoying noise of the fan should also be a thing of the past (I myself have not had any problems with the fan).