Originally Posted by frito
many FPS PC gamers can't play correctly on PC LCD's with input lag of more than 15 ms btw just for comparison.
i don't think that's true, though a lot of people would like to have you believe they can detect lag that low. do you really think there are many games out there that require the player to react before a single frame has passed? i'm guessing such an unforgiving window of timing would make a game unplayable for 99.99999% of us.
most of the games that require fast, twitch reactions from the player such as fighting games and the like generally give you as much as several hundred milliseconds to react- an amount that's literally about as fast as the blink of an eye. very few games (with the exception of music titles) require timing quicker than that. i doubt that shooting games where you compete against human opponents have matches decided by a single frame often.
i couldn't find the link, but there was a street fighter convention type thing recently where serious gamers were tested to see how much input lag they could notice. these are people who have played these fighting games for over a decade and participate in tournaments against the best players in the world. to put it bluntly, reflexes don't get faster than theirs; the average participant couldn't detect any lower than 30ms or 2 frames of lag.
you obviously still don't want any lag that doesn't have to be there, and even if it isn't a directly noticeable amount it still reduces your window to react, so it is a problem. but when people go around boasting about how they're sensitive enough that even 10ms throws them off i suspect they're full of it.