   System Timers are Slowing Down
  I have some Windows code for a timer that is pretty straight forward.  It calls QueryPerformanceFrequency to get the high perf clock freq and then calls QueryPerformanceCounter each frame at the beginning.  The code performs a Sleep(1) until a specified amount of time (33 ms) has passed.  This is all it does, just sleeps until X ms has passed to force a specific frame rate, I disabled all code running after this.What I'm seeing is that over time, after my PC has been running a while, the QPC return value doesn't change between calls.  So I sleep 1 ms, call QPC and the same integer is returned as the previous call before sleeping.  I do this repeatedly and then all of the sudden the returned value is a 10 ms or higher jump from the previous value (or any # of ms, 10 just example).  I've placed a hysteresis buffer in to be sure that's what is happening.I get the same problem with timeGetTime or getTickCount.  It gets worse over time.  If I reboot my PC, I get exactly 33.33 ms (30 Hz).  I run my PC for a few hours (just my PC, not the software in question), then it's running at 40.5 ms, then a day later at 60.4 ms, etc until just now it was running at 125 ms.  Then I rebooted and it went back to 33 ms.The best I can tell, there may be something wrong with my system, the CPU itself, or the motherboard.  I have a quad core 2.33 Intel and an EP45-UD3P Gigabyte motherboard.  Has anyone ever heard of this before?Thanks!Chris   