http://bugs.winehq.org/show_bug.cgi?id=29168
--- Comment #204 from Carsten Juttner carjay@gmx.net 2012-03-17 19:18:20 CDT --- (In reply to comment #200)
But I don't know if there is drift when windows updates the values either. Carsten, did your test program exhibit such drift? I.e. did they do 64 full updates every second, so the values would fall on every second boundary?
A quick test shows that on my Vista system each update seems to add a value of either 156000 or 156001 to InterruptTime and always 156000 for SystemTime.
This would hint that the "real" update is not occurring at 64Hz but rather around 64.102564Hz. Anyway, the values are quite consistent.
I guess there is not a lot of drift because the timer interrupt is hardware generated.
But I do not think it matters much since these timers are not documented officially so as long as they get updated around 64 Hz things should work ok.