Peripheral latency
Mice and keyboards all have latency. Things that can impact it are vast, but the main ones are whether it is wired or wireless; some of the modern gaming mice like the Corsair Slipstream hardware even have low latency in their wireless modes.
Switch latency is less of an issue these days, as the usual OMRON or similar switches are very good indeed. However, how the switch is pressed can be a big difference. Is there a pre-travel on the mouse button before it registers a click, does your mouse have a debounce timing adjustment to change the speed at which multiple clicks are registered? You get the idea.
Then you have the polling rate, which is typically 1000 Hz, but this can be up to 8000 Hz on some of the more high-end gaming mice these days. That’s how many times a second the device checks for an input. The processor in the mouse will then take that signal and send it to the PC, where it’ll come into the USB driver, and be processed by the OS.
A pro gaming mouse will typically take all this into account and promise lower latency. Of course, with an LDAT you can test this. You would be able to try two different gaming mice and see which is better for latency.
