That is the exact class i am using for the timing. It is highly accurate and that class is definetely not the problem. I know from a very accurate soundbased reaction time measuring device, that my reaction times are about twice as fast, and more consistent than the ones i measure using a SoundPlayer, StopWatch and a KeyDown event. I have the feeling that this is because of small delays everywhere in the system (Windows is not a RTOS), but i have no idea what to do about them. ASCII tables, HTML entities, types, string formats and more info for the nerdy coder at: www.codecharts.com