The platforms in question are running Windows XP, not Vista or Windows
7. How does this change the answer?
NTP will switch on the multi-media timers in Windows XP and achieve the
best performance I have seen on Windows systems. Temperature (or perhaps
CPU load causing temperature change in your case) seems to be the limiting
factor in the peak offset.
By the way, the hardware is a collection of 8-core HP Z800 workstations
connected together by copper gigabit ethernet links and local hub, with
one link going via the company network to the GPS network time server.
Joe Gwinn
Beware the 1Gb/s adapter settings, as Dave Hart mentioned. You may find
you get better timekeeping performance setting them to 100Mb/s.
You might consider providing a local, more precise NTP server with
something like a small, fan-less Intel Atom system running FreeBSD and
synched across the network to your GPS time server. You might be able to
keep a small box like that in a more temperature controlled environment,
but even without it might provide a way of smoothing out any jitter due to
your remote connection to the GPS server.
Another thought is to send 1PPS across the network (an old RS-232 link,
perhaps, just used as a direct connection, not for serial data), and
duplicate the PPS feed to your remote server locally. Then make an RS-232
level driver to send PPS to all your workstations. They get the precise
seconds from the PPS, and the nearest-second time from the network.
Cheers,
David
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