Human reaction times have nothing to do with perceived input latency. There is a latency budget that is different for every individual that determines whether o

Human reaction times have nothing to do with perceived input latency. There is a latency budget that is different for every individual that determines whether or not something will be an acceptable experience. This budget is divided between everything in the signal chain like the input devices, the computer/console, the monitor/tv, and any other processors along the signal path. Streaming games adds additional latency to the signal chain. Generously if your target is 60fps and you have a round trip latency to their server of 8ms, that's a half frame of added latency. On its own it's almost certainly imperceptible to most people, but it's not working in a vacuum and most people don't live right next to the datacenter. It can very easily go over the threshold for what is acceptable to most people.