Yes, that clockres program and the powercfg report are very interesting. And it nicely explains why it is so inconsistent:
- It depends on which application has set the lowest timer.
- It is rounded up or down from the last timer tick.
- Some Windows versions try to emulate a slower timer by waiting approximately 15.6 ms by skipping interrupts. That also means that they're not running in sync.
- Some Linuxes use a free running scheduler, which impacts VM's.
In short: it depends. Don't count on it taking a specific time.
Btw. The only good way to measure time in such cases is by using the functions that return the current CPU cycle count. Or an external RTC.
On second thought: the CPU cycle count depends on the power saving, so an external clock source is the only reliable way.