> Here is a short video from Microsoft (about 10 years old now) on the experience of using a touchscreen with 100ms of delay vs 1ms showing the steps in between. The difference is extraordinary for the user even if the end result is the same.
That’s additional input delay, not absolute latency.
More importantly, the visual effect you’re seeing isn’t the perception of input delay. It’s the positional difference between the finger location and the box location. Typing in a terminal doesn’t have the same visual difference. In fact, using a mouse doesn’t have the same visual difference because your finger isn’t right next to the screen for comparison. Try dragging a window across your screen right now. The “lag” is easily on the order of the 100ms shown in this demo, but you won’t find it anywhere near as disorienting because your finger isn’t on the screen for visual reference.
It’s not possible to have 1ms lag unless you have a 1000Hz screen and zero processing time for the inputs.
Compare that to the standard 60Hz displays that most laptops and cellular phones use. At 60Hz, the screen only updates once every 17ms. Add input lag, processing lag, rendering delay, buffering delay, and other delays and it’s nearly impossible to go from input to screen action in under 30ms. Most games are on the order of 60-80ms.
The individual pixels in your LCD can’t even toggle from black to white in 1ms.
A lot of the HN comments here are misunderstanding the time scales involved in all of this. For reference, a blink of an eye is about 100ms