This article applies to Domain Time II.

Last Updated: 04 Feb 2026
The five largest contributors to good time sync are time source, connection type, operating system version, CPU type, and power configuration.

Time Source
An IEEE-1588 Precision Time Protocol (PTPv2) Grandmaster appliance is the best time source. It allows clients (called "slaves" in PTP) to adjust the clock frequency second-by-second in order to minimize drift. Software-based grandmasters, regardless of the operating system, cannot achieve the same level of accuracy and predictability as hardware appliances. Hardware appliances typically use GNSS/GPS as their own source of time, and usually have special NICs that are optimized for placing packets on the wire that compensate for network stack latency within the appliance. Note: We highly recommend that clients using PTP also have an NTP or DT2 source configured. This secondary source is used at startup or any time the PTP grandmaster either drops offline or provides unexpected timestamps.
NTP appliances usually use GNSS/GPS, too, and are optimized for low-latency, consistent reply times. Software-based NTP/DT2 sources are much less accurate. NTP and DT2 are request-reply protocols, meaning that the time is only delivered to the client when the client requests it. For best results, you should have three or more NTP appliances, and set your clients to sample each of them. Set the check interval to the appropriate level to obtain the desired sync. For seconds or high milliseconds, twice daily might be sufficient. For sub-millisecond results, one minute is usually sufficient.
Connection Type
As noted at the top of this article, Internet, WAN, and Wi-Fi connections (regardless of the quality of the time source) will not perform well.
Wi-Fi, even if used to sync to a good time source on the local LAN, has a typical latency measured in the tens to hundreds of milliseconds. Worse, the request-response time will be different for each time sample. Clients relying on Wi-Fi should not expect sync better than a handful of milliseconds.
Corporate WANs, even low-latency point-to-point configurations, will not perform as well as local time sources. Special PTP hardware known as Boundary Clocks, can reduce, but not eliminate the instability that comes from a non-local time source.
Internet connections, especially if relying on Internet time sources, are subject to unpredictable latencies and poor synchronization results. Clients should not expect sync of better than a handful of milliseconds. Wi-Fi clients using Internet sources should expect sync in the hundreds of milliseconds, or possibly greater than 1 second.
Local LANs, using server-grade NICs, obtaining the time from an appliance on the same LAN, can provide sub-microsecond sync using PTP, or a handful of microseconds using NTP. Software-based PTP or NTP servers will not perform as well. Note: USB-to-Ethernet dongles/docks introduce an unpredictable and uneven packet latency. The quality of time sync using such adapters is better than Wi-Fi, but not as good as a "real" Ethernet port.
Operating System Version
For Windows, the newer the operating system, generally the better quality of synchronization. Specifically, Windows 10, Windows 11, Windows 2022, and Windows 2025 are the most stable versions currently available. (See KB2019.708 for information on software timestamping.)
For Linux, kernel version 3.0 or later with a timestamping NIC provides the best performance. DTLinux will automatically discover and use the highest level of timestamping available.
CPU Type
Desktop or server CPUs provide the best performance. CPUs designed for laptops or other low-power devices, regardless of how you configure the machine, will not perform as well as high-performance CPUs. The CPU is important for servicing interrupts in a consistent and timely fashion. Laptops and similar low-power devices use "mobile" CPUs that favor power conservation over performance. A mobile CPU cannot achieve the same level of synchronization as a desktop or server CPU.
Power Configuration
For machines where you want the best sync, set the Power Configuration plan to avoid low-power states, specifically disabling power-savings/sleep for the Ethernet adapter and PCIe system. On operating systems predating Windows 11 or Windows 2025, you should also disable CPU low-power states.