The Steam Deck portable game console has a number of features that allow the user to customize the set-top box, focusing either on image quality or on autonomy. It turns out that these functions have a downside.
Steam Deck users have found that activating the frame rate cap and display frame rate results in a significant increase in input lag.
By default, Steam Deck latency is 31.8ms. Activating the frame rate lock at 30 fps leads to an increase in the rate to 145.9 ms, that is, an increase of more than four times! But things are worst of all if you limit the frequency at around 20 fps, and lower the frame rate of the screen to 40 Hz. In this case, the delay will increase to 232 ms, that is, more than seven times relative to the base value.
There are also options with a slight increase in delay: you only need to limit the frame rate of the screen at around 50 or 40 Hz. In this case, the delay will increase by only 8%.
Most likely, the problem can be solved with a software update, so it’s up to Valve.