[ntp:questions] What level of timesynch error is typical on Win XP?

Alexander Petrov (Moscow, Russia) alpet1 at gmail.com
Thu Oct 21 05:51:44 UTC 2010

On 21 окт, 00:59, E-Mail Sent to this address will be added to the
BlackLists <N... at BlackList.Anitech-Systems.invalid> wrote:
> > By default, the timer resolution 15.625 ms (1/64 second),
> >  ... increase the timer resolution.
> Current PCs' HPET timer is in the few NanoSeconds range?
>  and the ACPI timer is in the few dozen NanoSeconds range?

Right algorithm for any (S)NTP request:

t1 = localTime
do { t2 = localTime ) while ( t1 == t2 );
rtd = rdtsc  // round trip delay
send request to server, with originate timestamp = t2
retrieve response from server
rtd = ( rdtsc - rtd ) / ratio

In local network I can synchronize computers in range +-200 µs, and in
internet = +- 400 µs if use NTP servers pool.
All programs work with these algorithms?

2All, may be interested : http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html

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