Valve has been hard at work deploying substantial updates to the Steam Deck over the past few weeks, with the optional beta version of the device's operating system already loaded with a number of much-needed improvements and upgrades. Not everything seems to be according to plan, however, as one Steam Deck user may have discovered a serious flaw.
Namely, Redditor Dacvak recently posted on the Steam Deck subreddit with a series of discoveries about the device's actual input latency, and things are not looking good. According to Dacvak's data, Steam Deck's implementation of a system-wide frame rate cap seems to effectively quadruple the amount of time that passes between the user input and its in-game effect.
Steam Deck's effective battery life has been one of its main faults from the very start, and to resolve the issue, Valve implemented a system-wide frame rate cap feature that allows users to fine-tune their games' performance and power draw for maximum effect. According to the data that Dacvak collected, however, enabling the frame rate cap will hugely increase the device's input latency, which can make games feel sluggish and unresponsive. Using the new 40Hz refresh mode without a frame cap, users can expect about 34 ms of delay, but a cap will increase that number to 120 ms, instead.
The introduction of a 40Hz refresh mode on Steam Deck was a widely lauded move due to it opening up an almost perfect balance between battery life and gameplay smoothness. If Dacvak's findings are correct, however, users may be subjecting themselves to a very substantial amount of input lag by enabling this option, and there doesn't seem to be a good way to resolve the problem at this time.
Dacvak mentioned that, depending on the specific frame rate cap and screen refresh rate settings that a user sets up on their Steam Deck, they could be getting substantially worse input lag than they would on a Nintendo Switch, for example. It's a potentially huge problem for fast-paced games where input lag can lead to fail states, and many users agreed that fixing this should be near the top of Valve's plans for the Steam Deck.
Generally speaking, even though the Steam Deck now has over 2,000 verified games, the device's software is still effectively in its beta testing stages. Key features are being added on a weekly basis, and device performance is being changed around to a substantial degree. These changes are, thankfully, for the better in most cases, but it's clear that Valve has got a long road ahead of it before SteamOS is polished up to a satisfying degree.