using System;
using System.Runtime.InteropServices;

public class Example
{
    [DllImport("kernel32.dll", SetLastError = true)]
    static extern bool GetSystemTimeAdjustment(out long lpTimeAdjustment,
                                               out long lpTimeIncrement,
                                               out bool lpTimeAdjustmentDisabled);

    public static void Main()
    {
        long timeAdjustment, timeIncrement = 0;
        bool timeAdjustmentDisabled;

        if (GetSystemTimeAdjustment(out timeAdjustment, out timeIncrement,
                                    out timeAdjustmentDisabled))
        {
            if (/*!*/timeAdjustmentDisabled)
                Console.WriteLine("System clock resolution: {0:N3} milliseconds",
                                  timeIncrement / 10000.0);
            else
                Console.WriteLine("Unable to determine system clock resolution.");
        }
        Console.ReadLine();
    }
}
// The example displays output like the following:
//        System clock resolution: 15.600 milliseconds

参考链接：

Timer.Interval 属性 (System.Timers) | Microsoft Docs