Windows-7 to Windows-10 - NTP improvements
Over the period from the end of July to the start of August 2015 a number of my PCs were upgraded from Windows-7 to Windows-10. As Windows-10 includes a more precise function for telling the system time (API details), NTP was able to use this function and deliver a substantial improvement in timekeeping.
As the function is already in Windows-8, those PCs upgraded from Windows-8 to Windows-10 already had the better timekeeping, which was unchanged after the upgrade.
What are the gains?
Both the offset and the jitter reported by NTP have dramatically improved, as the graphs from three PCs below demonstrate. Jitter is reduced from around 1 millisecond (the resolution of the PC's software clock under Win-7) to around 50 microseconds.
I have some other notes about quirks discovered during the upgrade here.
Here are the performance improvements seen in three PCs.
PC Molde - Intel Atom, 4 GB, 64-bit Windows
This PC is connected via a LAN to a four-port TP-Link TL-WA890EA "Entertainment hub", which is itself connected via Wi-Fi to stratum-1 NTP servers.
Jitter - reduced from an average 1.1 milliseconds down to an averaged value around 60 microseconds.
PC Puffin - Dell Inspiron 530S, Core 2 Duo, 3 GB, 32-bit
This PC is only operated during the working day, hence the coverage is not a 24 hour period, and there are more transients at the start of the graph. It has an AE1200 Wireless-N adapter plugged into one of its USB ports.
Jitter - reduced from an averaged value of 1 millisecond to around 50 microseconds.
PC Ystad - Samsung N150plus netbook, Intel N455, 2 GB, 32-bit
This PC is working directly with its built-in Wi-Fi port.
Jitter - again reduced from 1 millisecond to around 50 microseconds.