There is even a simpler solution to the problem that does not require a calibration. Our problem is that the synchronizing loop spends too much system time compared to user time. So just avoid the call to gettimeofday() in the loop, and call times() only. The return value of gettimeofday() is ignored anyway, at least inside the loop. Cheers, Guido -- Империя ООД | Imperia OOD ул. „Княз-Борис-I“ № 86, София 1000 | ul. "Knyaz-Boris-I" № 86, Sofia http://www.imperia.bg/Thread Previous