Hi, I can give more context on this setting. There's multiple API for fetching Raw Input. This setting does 2 things, it changes the API that is used by default in Unreal for Raw Input and coalesces input on click and frame boundaries when the input is read before sending it to application code.
With 8k hz mice, this has a very large performance impact and needs to be used with those mice for a playable experience. This was the largest motivation behind this setting.
With 1k mice, there is a modest performance gain, but not something that would be particularly noticeable to players given the variance in frame times throughout a round.
Functionally, there's not a difference from a player's perspective when using the setting, and if you are not using an 8k hz mouse, you should not be able to tell if the setting is on or not. That being said, the aggregate gains are enough that we believe there is value in making this the default for all players in the future regardless of the input device they use.
I have a draft for a Riot tech blog post about VALORANT's input that I'd like to publish soonTM that would go into more details on this, but its a bit lower on the priority list compared to some other work the performance team is doing.
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