Hi, > The "Enhanced Timer" section suggests that >QueryPerformanceCounter should really be constant frequency. I will >take another look at my code that uses it, and test it again.
the other pages state that the timer frequency changes along with the CPU frequency in some cases. As I understood it, QPC can use different timer sources on different systems (Windows picks the one it thinks to be the best), and some seem to be irreliable when the CPU frequency changes (e.g. because of SpeedStep/Cool'n'Quiet). The danger of Windows moving the process between CPUs shouldn't be a major problem as it could be eliminated by binding the thread to a CPU (with SetThreadAffinityMask), but the Cool'n'Quiet thing seems to be what renders QueryPerformanceCounter useless. After reading the links you sent, I still think the multimedia timer (timeGetTime) is the best thing to use although using multimedia libraries in a network client application feels kind of strange. Patrick
