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    <p>Based on the other solutions and comments, I put together this VB.NET code. Can be pasted into a project with a form. I understood @HansPassant's comments as saying that as long as <code>timeBeginPeriod</code> is called, the "regular timers get accurate as well". This doesn't seem to be the case in my code.</p> <p>My code creates a multimedia timer, a <code>System.Threading.Timer</code>, a <code>System.Timers.Timer</code>, and a <code>Windows.Forms.Timer</code> after using <code>timeBeginPeriod</code> to set the timer resolution to the minimum. The multimedia timer runs at 1 kHz as required, but the others still are stuck at 64 Hz. So either I'm doing something wrong, or there's no way to change the resolution of the built-in .NET timers.</p> <p><strong>EDIT</strong>; changed the code to use the StopWatch class for timing.</p> <pre><code>Imports System.Runtime.InteropServices Public Class Form1 'From http://www.pinvoke.net/default.aspx/winmm/MMRESULT.html Private Enum MMRESULT MMSYSERR_NOERROR = 0 MMSYSERR_ERROR = 1 MMSYSERR_BADDEVICEID = 2 MMSYSERR_NOTENABLED = 3 MMSYSERR_ALLOCATED = 4 MMSYSERR_INVALHANDLE = 5 MMSYSERR_NODRIVER = 6 MMSYSERR_NOMEM = 7 MMSYSERR_NOTSUPPORTED = 8 MMSYSERR_BADERRNUM = 9 MMSYSERR_INVALFLAG = 10 MMSYSERR_INVALPARAM = 11 MMSYSERR_HANDLEBUSY = 12 MMSYSERR_INVALIDALIAS = 13 MMSYSERR_BADDB = 14 MMSYSERR_KEYNOTFOUND = 15 MMSYSERR_READERROR = 16 MMSYSERR_WRITEERROR = 17 MMSYSERR_DELETEERROR = 18 MMSYSERR_VALNOTFOUND = 19 MMSYSERR_NODRIVERCB = 20 WAVERR_BADFORMAT = 32 WAVERR_STILLPLAYING = 33 WAVERR_UNPREPARED = 34 End Enum 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757625(v=vs.85).aspx &lt;StructLayout(LayoutKind.Sequential)&gt; Public Structure TIMECAPS Public periodMin As UInteger Public periodMax As UInteger End Structure 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757627(v=vs.85).aspx &lt;DllImport("winmm.dll")&gt; Private Shared Function timeGetDevCaps(ByRef ptc As TIMECAPS, ByVal cbtc As UInteger) As MMRESULT End Function 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757624(v=vs.85).aspx &lt;DllImport("winmm.dll")&gt; Private Shared Function timeBeginPeriod(ByVal uPeriod As UInteger) As MMRESULT End Function 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757626(v=vs.85).aspx &lt;DllImport("winmm.dll")&gt; Private Shared Function timeEndPeriod(ByVal uPeriod As UInteger) As MMRESULT End Function 'http://msdn.microsoft.com/en-us/library/windows/desktop/ff728861(v=vs.85).aspx Private Delegate Sub TIMECALLBACK(ByVal uTimerID As UInteger, _ ByVal uMsg As UInteger, _ ByVal dwUser As IntPtr, _ ByVal dw1 As IntPtr, _ ByVal dw2 As IntPtr) 'Straight from C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Include\MMSystem.h 'fuEvent below is a combination of these flags. Private Const TIME_ONESHOT As UInteger = 0 Private Const TIME_PERIODIC As UInteger = 1 Private Const TIME_CALLBACK_FUNCTION As UInteger = 0 Private Const TIME_CALLBACK_EVENT_SET As UInteger = &amp;H10 Private Const TIME_CALLBACK_EVENT_PULSE As UInteger = &amp;H20 Private Const TIME_KILL_SYNCHRONOUS As UInteger = &amp;H100 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757634(v=vs.85).aspx 'Documentation is self-contradicting. The return value is Uinteger, I'm guessing. '"Returns an identifier for the timer event if successful or an error otherwise. 'This function returns NULL if it fails and the timer event was not created." &lt;DllImport("winmm.dll")&gt; Private Shared Function timeSetEvent(ByVal uDelay As UInteger, _ ByVal uResolution As UInteger, _ ByVal TimeProc As TIMECALLBACK, _ ByVal dwUser As IntPtr, _ ByVal fuEvent As UInteger) As UInteger End Function 'http://msdn.microsoft.com/en-us/library/windows/desktop/dd757630(v=vs.85).aspx &lt;DllImport("winmm.dll")&gt; Private Shared Function timeKillEvent(ByVal uTimerID As UInteger) As MMRESULT End Function Private lblRate As New Windows.Forms.Label Private WithEvents tmrUI As New Windows.Forms.Timer Private WithEvents tmrWorkThreading As New System.Threading.Timer(AddressOf TimerTick) Private WithEvents tmrWorkTimers As New System.Timers.Timer Private WithEvents tmrWorkForm As New Windows.Forms.Timer Public Sub New() lblRate.AutoSize = True Me.Controls.Add(lblRate) InitializeComponent() End Sub Private Capability As New TIMECAPS Private Sub Form1_FormClosing(sender As Object, e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing timeKillEvent(dwUser) timeEndPeriod(Capability.periodMin) End Sub Private dwUser As UInteger = 0 Private Clock As New System.Diagnostics.Stopwatch Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) _ Handles MyBase.Load Dim Result As MMRESULT 'Get the min and max period Result = timeGetDevCaps(Capability, Marshal.SizeOf(Capability)) If Result &lt;&gt; MMRESULT.MMSYSERR_NOERROR Then MsgBox("timeGetDevCaps returned " + Result.ToString) Exit Sub End If 'Set to the minimum period. Result = timeBeginPeriod(Capability.periodMin) If Result &lt;&gt; MMRESULT.MMSYSERR_NOERROR Then MsgBox("timeBeginPeriod returned " + Result.ToString) Exit Sub End If Clock.Start() Dim uTimerID As UInteger uTimerID = timeSetEvent(Capability.periodMin, Capability.periodMin, _ New TIMECALLBACK(AddressOf MMCallBack), dwUser, _ TIME_PERIODIC Or TIME_CALLBACK_FUNCTION Or TIME_KILL_SYNCHRONOUS) If uTimerID = 0 Then MsgBox("timeSetEvent not successful.") Exit Sub End If tmrWorkThreading.Change(0, 1) tmrWorkTimers.Interval = 1 tmrWorkTimers.Enabled = True tmrWorkForm.Interval = 1 tmrWorkForm.Enabled = True tmrUI.Interval = 100 tmrUI.Enabled = True End Sub Private CounterThreading As Integer = 0 Private CounterTimers As Integer = 0 Private CounterForms As Integer = 0 Private CounterMM As Integer = 0 Private ReadOnly TimersLock As New Object Private Sub tmrWorkTimers_Elapsed(sender As Object, e As System.Timers.ElapsedEventArgs) _ Handles tmrWorkTimers.Elapsed SyncLock TimersLock CounterTimers += 1 End SyncLock End Sub Private ReadOnly ThreadingLock As New Object Private Sub TimerTick() SyncLock ThreadingLock CounterThreading += 1 End SyncLock End Sub Private ReadOnly MMLock As New Object Private Sub MMCallBack(ByVal uTimerID As UInteger, _ ByVal uMsg As UInteger, _ ByVal dwUser As IntPtr, _ ByVal dw1 As IntPtr, _ ByVal dw2 As IntPtr) SyncLock MMLock CounterMM += 1 End SyncLock End Sub Private ReadOnly FormLock As New Object Private Sub tmrWorkForm_Tick(sender As Object, e As System.EventArgs) Handles tmrWorkForm.Tick SyncLock FormLock CounterForms += 1 End SyncLock End Sub Private Sub tmrUI_Tick(sender As Object, e As System.EventArgs) _ Handles tmrUI.Tick Dim Secs As Integer = Clock.Elapsed.TotalSeconds If Secs &gt; 0 Then Dim TheText As String = "" TheText += "System.Threading.Timer " + (CounterThreading / Secs).ToString("#,##0.0") + "Hz" + vbCrLf TheText += "System.Timers.Timer " + (CounterTimers / Secs).ToString("#,##0.0") + "Hz" + vbCrLf TheText += "Windows.Forms.Timer " + (CounterForms / Secs).ToString("#,##0.0") + "Hz" + vbCrLf TheText += "Multimedia Timer " + (CounterMM / Secs).ToString("#,##0.0") + "Hz" lblRate.Text = TheText End If End Sub End Class </code></pre>
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