I'm trying to do it using two FILETIMEs, casting them to ULONGLONGs, substracting the ULONGLONGs, and dividing the result by 10000. But it's pretty slow, and I want to know if there is a better way to do it.I use c++ with visual studio 2008 express edition. This is what I'm using: FILETIME filetime,filetime2; GetSystemTimeAsFileTime(&filetime); Sleep(100); GetSystemTimeAsFileTime(&filetime2); ULONGLONG time1,time2; time1 = (((ULONGLONG) filetime.dwHighDateTime) << 32) + filetime.dwLowDateTime; time2 = (((ULONGLONG) filetime2.dwHighDateTime) << 32) + filetime2.dwLowDateTime; printf("ELAPSED TIME IN MS:%d",(int)((time2-time1)/10000));