RTD Refresh Interval

Excel does not update RTD data for every single update. It refreshes RTD data periodically based on a system-wide throttle interval named Excel.Application.RTD.ThrottleInterval. You can set the throttle interval with either Visual Basic/VBA or the Registry.

Set the throttle interval:

• Via Visual Basic / VBA: You can set Application.RTD.ThrottleInterval. in immediate mode or in a startup handler.

• Via the Registry: On startup, Excel initializes the throttle interval from the registry value.

For Excel 2002:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\
   Excel\Options\RTDThrottleInterval

For Excel 2003:

HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\
   Excel\Options\RTDThrottleInterval

Set the throttle interval to any one of the following values:

ThrottleInterval value	Effect
-1	Manual mode. Never automatically refreshes. Excel.Application.RTD.RefreshData must be called.
0	Checks for updates every chance it gets.
>0	Excel waits at least the specified number of milliseconds before getting updates.

For more information, please refer to the following Microsoft FAQ item from MSDN, which explains the details best:

http://msdn2.microsoft.com/en-us/library/
   aa140060(office.10).aspx#odc_xlrtdfaq_howconfigrtdthrottle