[ntp:questions] Re: Windows timekeeping - sudden degradation- why?

Martin Burnicki martin.burnicki at meinberg.de
Mon Dec 12 10:35:59 UTC 2005

David J Taylor wrote:
> I didn't know about the difference between the SMP and uniprocessor HAL -
> most interesting!  On this system the performance counter is 3.579... MHz
> (US colour TV!), as it is on the backup PC.  Both are uniprocessor
> systems.

Yes, that's the clock rate of the timer chip which is used in the
uniprocessor HAL.

If the SMP HAL is used then the performance counter frequency matches the
CPU clock.

> I wish I knew what I had changed, but I don't!  However, from my own tests
> the change will benefit all those systems no on XP SP2, so any SP1 systems
> still out there, plus all the Windows 2000 and (perhaps) the Windows NT
> systems.


Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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