it shouldn't because you're using it clientside. As long as the timer is set up properly it shouldn't causee too significant amount of lag. Worse case scenario increase the limit from say 1 second to every 5 seconds. I wrote a win32api prog a while back that was basically realtime, it didn't do much of anything, but it used timers.
elgbot 2 used timers, elgbot 3 has no timers . they both clear console, basicaly clearing a huge buffer.. why would that cause lag? it's client side too.