...there is not promised by OS and OS itself may not be deterministic. If you rally wanted to get precise numbers there you'd probably go for a 3rd party solution that makes the XP(e) real-time (TenAsys's INtime, ex-Venturcom's RTX). What you want to do to get more statistic data on the issues is as follows: - bump up your "waiting" thread priority to highest or time-critical. Especially ...