Considering also that most keyboards (even old PS2 keyboards) have an input delay no higher than ~15ms. Also, mechanical switches inherently have 'debounce' so there is basically "built in" input delay. IR/Optical switches have eliminated the debounce issue but are still mainly in a testing phase and not adapted by many. Add in the dead space of travel time to hit the keys actuation point and you are just adding up the milliseconds. Too many factors, besides the actual keyboard, affect this and is the main reason why I recommend people to choose a keyboard off of feel and how well it fits your application.